diff --git a/bin/sugar-install-bundle b/bin/sugar-install-bundle
index 883dbfb6..3cce4cb1 100755
--- a/bin/sugar-install-bundle
+++ b/bin/sugar-install-bundle
@@ -3,6 +3,9 @@ import sys
 
 from sugar.activity.bundle import Bundle
 
+from dbus.mainloop.glib import DBusGMainLoop
+DBusGMainLoop(set_as_default=True)
+
 bundle = Bundle(sys.argv[1])
 bundle.install()
 
diff --git a/shell/shellservice.py b/shell/shellservice.py
index b4c96ffc..c612d6e2 100644
--- a/shell/shellservice.py
+++ b/shell/shellservice.py
@@ -56,6 +56,9 @@ class ShellService(dbus.service.Object):
         self._home_model.connect('active-activity-changed',
                                  self._cur_activity_changed_cb)
 
+        bundle_registry = bundleregistry.get_registry()
+        bundle_registry.connect('bundle-added', self._bundle_added_cb)
+        
         bus = dbus.SessionBus()
         bus_name = dbus.service.BusName(_DBUS_SERVICE, bus=bus)
         dbus.service.Object.__init__(self, bus_name, _DBUS_PATH)
@@ -121,6 +124,10 @@ class ShellService(dbus.service.Object):
 
         return result
 
+    @dbus.service.signal(_DBUS_ACTIVITY_REGISTRY_IFACE, signature="a{sv}")
+    def ActivityAdded(self, activity_info):
+        pass
+
     @dbus.service.signal(_DBUS_OWNER_IFACE, signature="s")
     def ColorChanged(self, color):
         pass
@@ -158,3 +165,7 @@ class ShellService(dbus.service.Object):
                 'icon': bundle.get_icon(),
                 'service_name': bundle.get_service_name(),
                 'path': bundle.get_path()}
+
+    def _bundle_added_cb(self, bundle_registry, bundle):
+        self.ActivityAdded(self._bundle_to_dict(bundle))
+
diff --git a/sugar/activity/registry.py b/sugar/activity/registry.py
index 171f740e..b19abee6 100644
--- a/sugar/activity/registry.py
+++ b/sugar/activity/registry.py
@@ -15,6 +15,8 @@
 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.
 
+import logging
+
 import dbus
 
 _SHELL_SERVICE = "org.laptop.Shell"
@@ -39,6 +41,11 @@ class ActivityRegistry(object):
         bus = dbus.SessionBus()
         bus_object = bus.get_object(_SHELL_SERVICE, _SHELL_PATH)
         self._registry = dbus.Interface(bus_object, _REGISTRY_IFACE)
+        self._registry.connect_to_signal('ActivityAdded', self._activity_added_cb)
+
+        # Two caches fo saving some travel across dbus.
+        self._service_name_to_activity_info = {}
+        self._mime_type_to_activities = {}
 
     def _convert_info_list(self, info_list):
         result = []
@@ -49,16 +56,33 @@ class ActivityRegistry(object):
         return result
 
     def get_activity(self, service_name):
+        if self._service_name_to_activity_info.has_key(service_name):
+            return self._service_name_to_activity_info[service_name]
+
         info_dict = self._registry.GetActivity(service_name)
-        return _activity_info_from_dict(info_dict)
+        activity_info = _activity_info_from_dict(info_dict)
+
+        self._service_name_to_activity_info[service_name] = activity_info
+        return activity_info
 
     def find_activity(self, name):
         info_list = self._registry.FindActivity(name)
         return self._convert_info_list(info_list)
 
     def get_activities_for_type(self, mime_type):
+        if self._mime_type_to_activities.has_key(mime_type):
+            return self._mime_type_to_activities[mime_type]
+
         info_list = self._registry.GetActivitiesForType(mime_type)
-        return self._convert_info_list(info_list)
+        activities = self._convert_info_list(info_list)
+
+        self._mime_type_to_activities[mime_type] = activities
+        return activities
+
+    def _activity_added_cb(self, bundle):
+        logging.debug('ActivityRegistry._activity_added_cb: flushing caches')
+        self._service_name_to_activity_info.clear()
+        self._mime_type_to_activities.clear()
 
 _registry = None
 
diff --git a/sugar/objects/objecttype.py b/sugar/objects/objecttype.py
index dd2da548..a8192168 100644
--- a/sugar/objects/objecttype.py
+++ b/sugar/objects/objecttype.py
@@ -36,20 +36,39 @@ class ObjectType(object):
         self.name = name
         self.icon = icon
         self.mime_types = mime_types
+        
+        self._type_id_to_type = {}
+        self._mime_type_to_type = {}
 
 class ObjectTypeRegistry(object):
     def __init__(self):
         bus = dbus.SessionBus()
         bus_object = bus.get_object(_SERVICE, _PATH)
         self._registry = dbus.Interface(bus_object, _IFACE)
+        
+        # Two caches fo saving some travel across dbus.
+        self._type_id_to_type = {}
+        self._mime_type_to_type = {}
 
     def get_type(self, type_id):
+        if self._type_id_to_type.has_key(type_id):
+            return self._type_id_to_type[type_id]
+
         type_dict = self._registry.GetType(type_id)
-        return _object_type_from_dict(type_dict)
+        object_type = _object_type_from_dict(type_dict)
+
+        self._type_id_to_type[type_id] = object_type
+        return object_type
 
     def get_type_for_mime(self, mime_type):
+        if self._mime_type_to_type.has_key(mime_type):
+            return self._mime_type_to_type[mime_type]
+
         type_dict = self._registry.GetTypeForMIME(mime_type)
-        return _object_type_from_dict(type_dict)
+        object_type = _object_type_from_dict(type_dict)
+
+        self._mime_type_to_type[mime_type] = object_type
+        return object_type
 
 _registry = None