diff --git a/django/contrib/admin/sites.py b/django/contrib/admin/sites.py
index 522032ec8d..b236dc8f93 100644
--- a/django/contrib/admin/sites.py
+++ b/django/contrib/admin/sites.py
@@ -53,12 +53,14 @@ def _decode_post_data(encoded_data):
 
 class AdminSite(object):
     def __init__(self):
-        self._registry = {} # model_class -> admin_class
+        self._registry = {} # model_class class -> admin_class instance
 
     def register(self, model_or_iterable, admin_class=None, **options):
         """
         Registers the given model(s) with the given admin class.
 
+        The model(s) should be Model classes, not instances.
+
         If an admin class isn't given, it will use ModelAdmin (the default
         admin options). If keyword arguments are given -- e.g., list_display --
         they'll be applied as options to the admin class.
@@ -72,7 +74,7 @@ class AdminSite(object):
         for model in model_or_iterable:
             if model in self._registry:
                 raise AlreadyRegistered('The model %s is already registered' % model.__class__.__name__)
-            self._registry[model] = admin_class
+            self._registry[model] = admin_class(model)
 
     def unregister(self, model_or_iterable):
         """
@@ -100,25 +102,80 @@ class AdminSite(object):
 
         `url` is the remainder of the URL -- e.g. 'comments/comment/'.
         """
+        url = url.rstrip('/') # Trim trailing slash, if it exists.
+
+        # The 'logout' view doesn't require that the person is logged in.
+        if url == 'logout':
+            return self.logout(request)
+
         if not self.has_permission(request):
             return self.login(request)
-        url = url.rstrip('/') # Trim trailing slash, if it exists.
+
         if url == '':
             return self.index(request)
         elif url == 'password_change':
             return self.password_change(request)
         elif url == 'password_change/done':
             return self.password_change_done(request)
-        raise NotImplementedError('Only the admin index page is implemented.')
+        elif url == 'jsi18n':
+            return self.i18n_javascript(request)
+        elif '/' in url:
+            return self.model_page(request, *url.split('/', 2))
+
+        raise http.Http404('The requested admin page does not exist.')
+
+    def model_page(self, request, app_label, model_name, rest_of_url=None):
+        """
+        Handles the model-specific functionality of the admin site, delegating
+        to the appropriate ModelAdmin class.
+        """
+        from django.db import models
+        model = models.get_model(app_label, model_name)
+        if model is None:
+            raise http.Http404("App %r, model %r, not found." % (app_label, model_name))
+        try:
+            admin_obj = self._registry[model]
+        except KeyError:
+            raise http.Http404("This model exists but has not been registered with the admin site.")
+        return admin_obj(request, rest_of_url)
 
     def password_change(self, request):
+        """
+        Handles the "change password" task -- both form display and validation.
+        """
         from django.contrib.auth.views import password_change
         return password_change(request)
 
     def password_change_done(self, request):
+        """
+        Displays the "success" page after a password change.
+        """
         from django.contrib.auth.views import password_change_done
         return password_change_done(request)
 
+    def i18n_javascript(self, request):
+        """
+        Displays the i18n JavaScript that the Django admin requires.
+
+        This takes into account the USE_I18N setting. If it's set to False, the
+        generated JavaScript will be leaner and faster.
+        """
+        from django.conf import settings
+        if settings.USE_I18N:
+            from django.views.i18n import javascript_catalog
+        else:
+            from django.views.i18n import null_javascript_catalog as javascript_catalog
+        return javascript_catalog(request, packages='django.conf')
+
+    def logout(self, request):
+        """
+        Logs out the user for the given HttpRequest.
+
+        This should *not* assume the user is already logged in.
+        """
+        from django.contrib.auth.views import logout
+        return logout(request)
+
     def login(self, request):
         """
         Displays the login form for the given HttpRequest.
@@ -173,6 +230,10 @@ class AdminSite(object):
                 return _display_login_form(request, ERROR_MESSAGE)
 
     def index(self, request):
+        """
+        Displays the main admin index page, which lists all of the installed
+        apps that have been registered in this site.
+        """
         app_list = []
         user = request.user
         for model, model_admin in self._registry.items():