Index: test/test_gogrid.py
===================================================================
--- test/test_gogrid.py	(revision 982615)
+++ test/test_gogrid.py	(working copy)
@@ -20,6 +20,7 @@
 except ImportError:
     import simplejson as json
 
+from libcloud.types import LibCloudException
 from libcloud.drivers.gogrid import GoGridNodeDriver
 from libcloud.base import Node, NodeImage, NodeSize
 
@@ -32,6 +33,7 @@
 
     def setUp(self):
         GoGridNodeDriver.connectionCls.conn_classes = (None, GoGridMockHttp)
+        GoGridMockHttp.type = None
         self.driver = GoGridNodeDriver("foo", "bar")
 
     def test_create_node(self):
@@ -66,6 +68,15 @@
         self.assertEqual(image.name, 'CentOS 5.3 (32-bit) w/ None')
         self.assertEqual(image.id, 1531)
 
+    def test_malformed_reply(self):
+        GoGridMockHttp.type = 'FAIL'
+        try:
+            images = self.driver.list_images()
+        except LibCloudException, e:
+            self.assertEqual(True, isinstance(e, LibCloudException))
+        else:
+            self.fail("test should have thrown")
+
 class GoGridMockHttp(MockHttp):
 
     fixtures = FileFixtures('gogrid')
@@ -74,6 +85,10 @@
         body = self.fixtures.load('image_list.json')
         return (httplib.OK, body, {}, httplib.responses[httplib.OK])
 
+    def _api_grid_image_list_FAIL(self, method, url, body, headers):
+        body = "<h3>some non valid json here</h3>"
+        return (httplib.SERVICE_UNAVAILABLE, body, {}, httplib.responses[httplib.SERVICE_UNAVAILABLE])
+
     def _api_grid_server_list(self, method, url, body, headers):
         body = self.fixtures.load('server_list.json')
         return (httplib.OK, body, {}, httplib.responses[httplib.OK])
Index: libcloud/types.py
===================================================================
--- libcloud/types.py	(revision 982615)
+++ libcloud/types.py	(working copy)
@@ -73,14 +73,16 @@
     PENDING = 3
     UNKNOWN = 4
 
-class InvalidCredsException(Exception):
+class LibCloudException(Exception): pass
+
+class InvalidCredsException(LibCloudException):
     """Exception used when invalid credentials are used on a provider."""
     def __init__(self, value='Invalid credentials with the provider'):
         self.value = value
     def __str__(self):
         return repr(self.value)
 
-class DeploymentException(Exception):
+class DeploymentException(LibCloudException):
     """
     Exception used when a Deployment Task failed.
 
Index: libcloud/drivers/gogrid.py
===================================================================
--- libcloud/drivers/gogrid.py	(revision 982615)
+++ libcloud/drivers/gogrid.py	(working copy)
@@ -16,7 +16,7 @@
 GoGrid driver
 """
 from libcloud.providers import Provider
-from libcloud.types import NodeState, InvalidCredsException
+from libcloud.types import NodeState, LibCloudException, InvalidCredsException
 from libcloud.base import Node, ConnectionUserAndKey, Response, NodeDriver
 from libcloud.base import NodeSize, NodeImage, NodeLocation
 import time
@@ -78,7 +78,10 @@
             raise InvalidCredsException()
         if not self.body:
             return None
-        return json.loads(self.body)['status'] == 'success'
+        try:
+            return json.loads(self.body)['status'] == 'success'
+        except ValueError:
+            raise LibCloudException('Malformed reply')
 
     def parse_body(self):
         if not self.body: