diff --git a/pkg/config/admin_scopes.go b/pkg/config/admin_scopes.go
index c561b57..d71d430 100644
--- a/pkg/config/admin_scopes.go
+++ b/pkg/config/admin_scopes.go
@@ -23,8 +23,10 @@ const (
 	// Website administration
 	// - Forum: ability to manage available forums
 	// - Scopes: ability to manage admin groups & scopes
+	// - Maintenance mode
 	ScopeForumAdmin      = "admin.forum.manage"
 	ScopeAdminScopeAdmin = "admin.scope.manage"
+	ScopeMaintenance     = "admin.maintenance"
 
 	// User account admin
 	// - Impersonate: ability to log in as a user account
@@ -35,6 +37,9 @@ const (
 	ScopeUserPromote     = "admin.user.promote"
 	ScopeUserDelete      = "admin.user.delete"
 
+	// Admins with this scope can not be blocked by users.
+	ScopeUnblockable = "admin.unblockable"
+
 	// Special scope to mark an admin automagically in the Inner Circle
 	ScopeIsInnerCircle = "admin.override.inner-circle"
 )
@@ -61,6 +66,7 @@ func ListAdminScopes() []string {
 		ScopeUserBan,
 		ScopeUserDelete,
 		ScopeUserPromote,
+		ScopeUnblockable,
 		ScopeIsInnerCircle,
 	}
 }
diff --git a/pkg/config/variable.go b/pkg/config/variable.go
index 1325d99..17bd5ab 100644
--- a/pkg/config/variable.go
+++ b/pkg/config/variable.go
@@ -11,11 +11,16 @@ import (
 	"github.com/google/uuid"
 )
 
+// Version of the config format - when new fields are added, it will attempt
+// to write the settings.toml to disk so new defaults populate.
+var currentVersion = 1
+
 // Current loaded settings.json
 var Current = DefaultVariable()
 
 // Variable configuration attributes (loaded from settings.json).
 type Variable struct {
+	Version          int
 	BaseURL          string
 	AdminEmail       string
 	CronAPIKey       string
@@ -23,6 +28,7 @@ type Variable struct {
 	Redis            Redis
 	Database         Database
 	BareRTC          BareRTC
+	Maintenance      Maintenance
 	UseXForwardedFor bool
 }
 
@@ -65,15 +71,7 @@ func LoadSettings() {
 
 		Current = v
 	} else {
-		var buf bytes.Buffer
-		enc := json.NewEncoder(&buf)
-		enc.SetIndent("", "    ")
-		err := enc.Encode(DefaultVariable())
-		if err != nil {
-			panic(fmt.Sprintf("LoadSettings: couldn't marshal default settings: %s", err))
-		}
-
-		ioutil.WriteFile(SettingsPath, buf.Bytes(), 0600)
+		WriteSettings()
 		log.Warn("NOTICE: Created default settings.json file - review it and configure mail servers and database!")
 	}
 
@@ -82,6 +80,30 @@ func LoadSettings() {
 		log.Error("No database configured in settings.json. Choose SQLite or Postgres and update the DB connector string!")
 		os.Exit(1)
 	}
+
+	// Have we added new config fields? Save the settings.json.
+	if Current.Version != currentVersion {
+		log.Warn("New options are available for your settings.json file. Your settings will be re-saved now.")
+		Current.Version = currentVersion
+		if err := WriteSettings(); err != nil {
+			log.Error("Couldn't write your settings.json file: %s", err)
+		}
+	}
+}
+
+// WriteSettings will commit the settings.json to disk.
+func WriteSettings() error {
+	log.Error("Note: initial settings.json was written to disk.")
+
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	enc.SetIndent("", "    ")
+	err := enc.Encode(Current)
+	if err != nil {
+		panic(fmt.Sprintf("WriteSettings: couldn't marshal settings: %s", err))
+	}
+
+	return ioutil.WriteFile(SettingsPath, buf.Bytes(), 0600)
 }
 
 // Mail settings.
@@ -114,3 +136,11 @@ type BareRTC struct {
 	JWTSecret string
 	URL       string
 }
+
+// Maintenance mode settings.
+type Maintenance struct {
+	PauseSignup      bool
+	PauseLogin       bool
+	PauseChat        bool
+	PauseInteraction bool
+}
diff --git a/pkg/controller/account/login.go b/pkg/controller/account/login.go
index 216a4de..7f2e2f6 100644
--- a/pkg/controller/account/login.go
+++ b/pkg/controller/account/login.go
@@ -6,6 +6,7 @@ import (
 
 	"code.nonshy.com/nonshy/website/pkg/config"
 	"code.nonshy.com/nonshy/website/pkg/log"
+	"code.nonshy.com/nonshy/website/pkg/middleware"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/ratelimit"
 	"code.nonshy.com/nonshy/website/pkg/session"
@@ -70,6 +71,11 @@ func Login() http.HandlerFunc {
 				return
 			}
 
+			// Maintenance mode check.
+			if middleware.LoginMaintenance(user, w, r) {
+				return
+			}
+
 			// OK. Log in the user's session.
 			session.LoginUser(w, r, user)
 
diff --git a/pkg/controller/account/profile.go b/pkg/controller/account/profile.go
index efcc69a..ffda661 100644
--- a/pkg/controller/account/profile.go
+++ b/pkg/controller/account/profile.go
@@ -5,6 +5,7 @@ import (
 	"net/url"
 	"regexp"
 
+	"code.nonshy.com/nonshy/website/pkg/middleware"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/session"
 	"code.nonshy.com/nonshy/website/pkg/templates"
@@ -51,6 +52,11 @@ func Profile() http.HandlerFunc {
 			return
 		}
 
+		// Is the site under a Maintenance Mode restriction?
+		if middleware.MaintenanceMode(currentUser, w, r) {
+			return
+		}
+
 		// Forcing an external view? (preview of logged-out profile view for visibility=external accounts)
 		// You must be logged-in actually to see this.
 		if r.FormValue("view") == "external" {
diff --git a/pkg/controller/account/signup.go b/pkg/controller/account/signup.go
index b3d9e4d..56c05fa 100644
--- a/pkg/controller/account/signup.go
+++ b/pkg/controller/account/signup.go
@@ -10,6 +10,7 @@ import (
 	"code.nonshy.com/nonshy/website/pkg/config"
 	"code.nonshy.com/nonshy/website/pkg/log"
 	"code.nonshy.com/nonshy/website/pkg/mail"
+	"code.nonshy.com/nonshy/website/pkg/middleware"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/redis"
 	"code.nonshy.com/nonshy/website/pkg/session"
@@ -35,6 +36,11 @@ func Signup() http.HandlerFunc {
 	tmpl := templates.Must("account/signup.html")
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Maintenance mode?
+		if middleware.SignupMaintenance(w, r) {
+			return
+		}
+
 		// Template vars.
 		var vars = map[string]interface{}{
 			"SignupToken":           "",    // non-empty if user has clicked verification link
diff --git a/pkg/controller/admin/maintenance.go b/pkg/controller/admin/maintenance.go
new file mode 100644
index 0000000..c14c880
--- /dev/null
+++ b/pkg/controller/admin/maintenance.go
@@ -0,0 +1,73 @@
+package admin
+
+import (
+	"net/http"
+
+	"code.nonshy.com/nonshy/website/pkg/config"
+	"code.nonshy.com/nonshy/website/pkg/session"
+	"code.nonshy.com/nonshy/website/pkg/templates"
+)
+
+// Maintenance controller (/admin/maintenance)
+func Maintenance() http.HandlerFunc {
+	tmpl := templates.Must("admin/maintenance.html")
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Query parameters.
+		var (
+			intent = r.FormValue("intent")
+		)
+
+		currentUser, err := session.CurrentUser(r)
+		if err != nil {
+			session.FlashError(w, r, "Couldn't get your current user: %s", err)
+		}
+
+		_ = currentUser
+
+		// POST event handlers.
+		if r.Method == http.MethodPost {
+			// Collect the form parameters.
+			var (
+				pauseSignup      = r.PostFormValue("signup") == "true"
+				pauseLogin       = r.PostFormValue("login") == "true"
+				pauseChat        = r.PostFormValue("chat") == "true"
+				pauseInteraction = r.PostFormValue("interaction") == "true"
+			)
+
+			switch intent {
+			case "everything", "nothing":
+				pauseSignup = intent == "everything"
+				pauseLogin = pauseSignup
+				pauseChat = pauseSignup
+				pauseInteraction = pauseSignup
+				intent = "save"
+				fallthrough
+			case "save":
+				// Update and save the site settings.
+				config.Current.Maintenance.PauseSignup = pauseSignup
+				config.Current.Maintenance.PauseLogin = pauseLogin
+				config.Current.Maintenance.PauseChat = pauseChat
+				config.Current.Maintenance.PauseInteraction = pauseInteraction
+				if err := config.WriteSettings(); err != nil {
+					session.FlashError(w, r, "Couldn't write settings.json: %s", err)
+				} else {
+					session.Flash(w, r, "Maintenance settings updated!")
+				}
+			default:
+				session.FlashError(w, r, "Unsupported intent: %s", intent)
+			}
+
+			templates.Redirect(w, r.URL.Path)
+			return
+		}
+
+		var vars = map[string]interface{}{
+			"Intent": intent,
+			"Maint":  config.Current.Maintenance,
+		}
+		if err := tmpl.Execute(w, r, vars); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+}
diff --git a/pkg/controller/block/block.go b/pkg/controller/block/block.go
index 3763c41..b83b12c 100644
--- a/pkg/controller/block/block.go
+++ b/pkg/controller/block/block.go
@@ -108,8 +108,8 @@ func BlockUser() http.HandlerFunc {
 			return
 		}
 
-		// Can't block admins.
-		if user.IsAdmin {
+		// Can't block admins who have the unblockable scope.
+		if user.IsAdmin && user.HasAdminScope(config.ScopeUnblockable) {
 			// For curiosity's sake, log a report.
 			fb := &models.Feedback{
 				Intent:  "report",
diff --git a/pkg/controller/chat/chat.go b/pkg/controller/chat/chat.go
index 15fb3d9..a9aa0f7 100644
--- a/pkg/controller/chat/chat.go
+++ b/pkg/controller/chat/chat.go
@@ -12,6 +12,7 @@ import (
 	"code.nonshy.com/nonshy/website/pkg/config"
 	"code.nonshy.com/nonshy/website/pkg/geoip"
 	"code.nonshy.com/nonshy/website/pkg/log"
+	"code.nonshy.com/nonshy/website/pkg/middleware"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/photo"
 	"code.nonshy.com/nonshy/website/pkg/session"
@@ -67,6 +68,11 @@ func Landing() http.HandlerFunc {
 			isShy  = currentUser.IsShy()
 		)
 		if intent == "join" {
+			// Maintenance mode?
+			if middleware.ChatMaintenance(currentUser, w, r) {
+				return
+			}
+
 			// If we are shy, block chat for now.
 			if isShy {
 				session.FlashError(w, r,
diff --git a/pkg/middleware/authentication.go b/pkg/middleware/authentication.go
index db3fc35..5e68444 100644
--- a/pkg/middleware/authentication.go
+++ b/pkg/middleware/authentication.go
@@ -40,6 +40,11 @@ func LoginRequired(handler http.Handler) http.Handler {
 			return
 		}
 
+		// Is the site under a Maintenance Mode restriction?
+		if MaintenanceMode(user, w, r) {
+			return
+		}
+
 		// Ping LastLoginAt for long lived sessions, but not if impersonated.
 		if time.Since(user.LastLoginAt) > config.LastLoginAtCooldown && !session.Impersonated(r) {
 			user.LastLoginAt = time.Now()
@@ -123,6 +128,11 @@ func CertRequired(handler http.Handler) http.Handler {
 			return
 		}
 
+		// Is the site under a Maintenance Mode restriction?
+		if MaintenanceMode(currentUser, w, r) {
+			return
+		}
+
 		// User must be certified.
 		if !currentUser.Certified || currentUser.ProfilePhoto.ID == 0 {
 			log.Error("CertRequired: user is not certified")
diff --git a/pkg/middleware/maintenance.go b/pkg/middleware/maintenance.go
new file mode 100644
index 0000000..ae575a5
--- /dev/null
+++ b/pkg/middleware/maintenance.go
@@ -0,0 +1,71 @@
+package middleware
+
+import (
+	"net/http"
+
+	"code.nonshy.com/nonshy/website/pkg/config"
+	"code.nonshy.com/nonshy/website/pkg/models"
+	"code.nonshy.com/nonshy/website/pkg/templates"
+)
+
+var tmplMaint = templates.Must("errors/maintenance.html")
+
+// MaintenanceMode check at the middleware level, e.g. to block
+// LoginRequired and CertificationRequired if site-wide interaction
+// is currently on hold. Returns true if handled.
+func MaintenanceMode(currentUser *models.User, w http.ResponseWriter, r *http.Request) bool {
+	// Is the site under a Maintenance Mode restriction?
+	if config.Current.Maintenance.PauseInteraction && !currentUser.IsAdmin {
+		var vars = map[string]interface{}{
+			"Reason": "interaction",
+		}
+		if err := tmplMaint.Execute(w, r, vars); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		return true
+	}
+
+	return false
+}
+
+// SignupMaintenance may handle maintenance mode requests for signup gating.
+func SignupMaintenance(w http.ResponseWriter, r *http.Request) bool {
+	if config.Current.Maintenance.PauseSignup {
+		var vars = map[string]interface{}{
+			"Reason": "signup",
+		}
+		if err := tmplMaint.Execute(w, r, vars); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		return true
+	}
+	return false
+}
+
+// LoginMaintenance may handle maintenance mode requests for login gating.
+func LoginMaintenance(currentUser *models.User, w http.ResponseWriter, r *http.Request) bool {
+	if config.Current.Maintenance.PauseLogin && !currentUser.IsAdmin {
+		var vars = map[string]interface{}{
+			"Reason": "login",
+		}
+		if err := tmplMaint.Execute(w, r, vars); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		return true
+	}
+	return false
+}
+
+// ChatMaintenance may handle maintenance mode requests for chat room gating.
+func ChatMaintenance(currentUser *models.User, w http.ResponseWriter, r *http.Request) bool {
+	if config.Current.Maintenance.PauseChat && !currentUser.IsAdmin {
+		var vars = map[string]interface{}{
+			"Reason": "chat",
+		}
+		if err := tmplMaint.Execute(w, r, vars); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		return true
+	}
+	return false
+}
diff --git a/pkg/router/router.go b/pkg/router/router.go
index 4fe56f5..50b770a 100644
--- a/pkg/router/router.go
+++ b/pkg/router/router.go
@@ -87,6 +87,7 @@ func New() http.Handler {
 	mux.Handle("/admin/photo/certification", middleware.AdminRequired("", photo.AdminCertification()))
 	mux.Handle("/admin/feedback", middleware.AdminRequired("", admin.Feedback()))
 	mux.Handle("/admin/user-action", middleware.AdminRequired("", admin.UserActions()))
+	mux.Handle("/admin/maintenance", middleware.AdminRequired(config.ScopeMaintenance, admin.Maintenance()))
 	mux.Handle("/forum/admin", middleware.AdminRequired(config.ScopeForumAdmin, forum.Manage()))
 	mux.Handle("/forum/admin/edit", middleware.AdminRequired(config.ScopeForumAdmin, forum.AddEdit()))
 	mux.Handle("/inner-circle/remove", middleware.AdminRequired(config.ScopeCircleModerator, account.RemoveCircle()))
diff --git a/web/templates/admin/dashboard.html b/web/templates/admin/dashboard.html
index 822929e..78f7e6e 100644
--- a/web/templates/admin/dashboard.html
+++ b/web/templates/admin/dashboard.html
@@ -148,6 +148,12 @@
                                     Admin Permissions Management
                                 </a>
                             </li>
+                            <li>
+                                <a href="/admin/maintenance">
+                                    <i class="fa fa-wrench mr-2"></i>
+                                    Maintenance Mode
+                                </a>
+                            </li>
                         </ul>
                     </div>
                 </div>
diff --git a/web/templates/admin/maintenance.html b/web/templates/admin/maintenance.html
new file mode 100644
index 0000000..20eaa5c
--- /dev/null
+++ b/web/templates/admin/maintenance.html
@@ -0,0 +1,108 @@
+{{define "title"}}Admin - Maintenance Mode{{end}}
+{{define "content"}}
+{{$Root := .}}
+<div class="container">
+    <section class="hero is-danger is-bold">
+        <div class="hero-body">
+            <div class="container">
+                <h1 class="title">
+                    Maintenance Mode
+                </h1>
+            </div>
+        </div>
+    </section>
+
+    <form method="POST" action="{{.Request.URL.Path}}">
+        {{InputCSRF}}
+        <div class="p-4">
+
+            <p class="block">
+                This page allows you to set various Maintenance Mode flags that can pause or
+                disable website features if needed.
+                In an emergency, click on the Lock Down Everything button that will enable ALL maintenance
+                mode flags and basically disable the whole website for everybody except admin user accounts.
+            </p>
+
+            <p class="block">
+                <button type="submit" class="button is-danger mr-2"
+                    name="intent" value="everything"
+                    onclick="return confirm('Do you want to lock down EVERYTHING?')">
+                    <i class="fa fa-exclamation-triangle mr-2"></i> Lock Down Everything
+                </button>
+
+                <button type="submit" class="button is-success"
+                    name="intent" value="nothing"
+                    onclick="return confirm('Do you want to RESTORE ALL site functionality?')">
+                    <i class="fa fa-exclamation-triangle mr-2"></i> Restore Everything
+                </button>
+            </p>
+
+            <hr>
+
+            <label class="label">Maintenance Mode Settings</label>
+
+            <div class="field">
+                <label class="checkbox">
+                    <input type="checkbox"
+                        name="signup"
+                        value="true"
+                        {{if .Maint.PauseSignup}}checked{{end}}>
+                    Pause new account signups
+                </label>
+                <p class="help">
+                    New account signups are paused and a maintenance page is shown in its place.
+                </p>
+            </div>
+
+            <div class="field">
+                <label class="checkbox">
+                    <input type="checkbox"
+                        name="login"
+                        value="true"
+                        {{if .Maint.PauseLogin}}checked{{end}}>
+                    Pause new logins
+                </label>
+                <p class="help">
+                    The login page is disabled (except for admin user login). Already logged-in
+                    users can remain logged in.
+                </p>
+            </div>
+
+            <div class="field">
+                <label class="checkbox">
+                    <input type="checkbox"
+                        name="chat"
+                        value="true"
+                        {{if .Maint.PauseChat}}checked{{end}}>
+                    Pause chat room entry
+                </label>
+                <p class="help">
+                    No new entries into the chat room are allowed.
+                </p>
+            </div>
+
+            <div class="field">
+                <label class="checkbox">
+                    <input type="checkbox"
+                        name="interaction"
+                        value="true"
+                        {{if .Maint.PauseInteraction}}checked{{end}}>
+                    Pause <strong>all</strong> interactions
+                </label>
+                <p class="help">
+                    Every site feature becomes basically 'admin required' and users are given an error
+                    page where their only option is to log out or come back later.
+                </p>
+            </div>
+
+            <div class="block">
+                <button type="submit" class="button is-primary"
+                    name="intent" value="save">
+                    Save Settings
+                </button>
+            </div>
+
+        </div>
+
+</div>
+{{end}}
diff --git a/web/templates/errors/maintenance.html b/web/templates/errors/maintenance.html
new file mode 100644
index 0000000..88ab2d7
--- /dev/null
+++ b/web/templates/errors/maintenance.html
@@ -0,0 +1,61 @@
+{{define "title"}}Not Available{{end}}
+{{define "content"}}
+<div class="container">
+    <section class="hero block is-warning is-bold">
+        <div class="hero-body">
+            <div class="container">
+                <h1 class="title">Not Available</h1>
+                <h2 class="subtitle">The website is currently unavailable</h2>
+            </div>
+        </div>
+    </section>
+
+    <div class="block content p-4 mb-0">
+        <h1>{{PrettyTitle}} is currently not available</h1>
+        <p>
+            We regret to inform you that {{PrettyTitle}} is currently not available.
+        </p>
+
+        <p>
+            The website is currently in "maintenance mode" and the feature you requested
+            is currently on pause. Please check back again later.
+        </p>
+
+        <!-- More information? -->
+        {{if .Reason}}
+            <h2>More Information</h2>
+        {{end}}
+
+        {{if eq .Reason "interaction"}}
+        <p>
+            All user interaction on the website is currently on pause. You are currently
+            logged in to an account (username: {{.CurrentUser.Username}}) and you may
+            remain logged-in if you want, but all actions that require a logged-in account
+            are currently disabled.
+        </p>
+
+        <p>
+            If you'd like, you may <a href="/logout">log out</a> or just come back later
+            and see if the maintenance mode of the website has been lifted.
+        </p>
+        {{else if eq .Reason "signup"}}
+        <p>
+            All new account signups are currently on pause. We are not accepting any new
+            members at this time. Please check back again later.
+        </p>
+        {{else if eq .Reason "login"}}
+        <p>
+            All new account logins are currently on pause. Please try again later.
+        </p>
+        {{else if eq .Reason "chat"}}
+        <p>
+            The chat room is currently offline for maintenance. Please try again some other time.
+        </p>
+        {{else}}
+        <p>
+            No further information is available at this time.
+        </p>
+        {{end}}
+    </div>
+</div>
+{{end}}