diff --git a/IPython/testing/iptest.py b/IPython/testing/iptest.py
index 262ef28e2..14f8eba11 100644
--- a/IPython/testing/iptest.py
+++ b/IPython/testing/iptest.py
@@ -1,16 +1,52 @@
-#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 """IPython Test Suite Runner.
+
+This module provides a main entry point to a user script to test IPython itself
+from the command line.  The main() routine can be used in a similar manner to
+the ``nosetests`` script, and it takes similar arguments, but if no arguments
+are given it defaults to testing all of IPython.  This should be preferred to
+using plain ``nosetests`` because a number of nose plugins necessary to test
+IPython correctly are automatically configured by this code.
 """
 
+#-----------------------------------------------------------------------------
+# Module imports
+#-----------------------------------------------------------------------------
+
+# stdlib
 import sys
 import warnings
 
-from nose.core import TestProgram
+# third-party
 import nose.plugins.builtin
+from nose.core import TestProgram
 
+# Our own imports
 from IPython.testing.plugin.ipdoctest import IPythonDoctest
 
+#-----------------------------------------------------------------------------
+# Constants and globals
+#-----------------------------------------------------------------------------
+
+# For the IPythonDoctest plugin, we need to exclude certain patterns that cause
+# testing problems.  We should strive to minimize the number of skipped
+# modules, since this means untested code.  As the testing machinery
+# solidifies, this list should eventually become empty.
+EXCLUDE = ['IPython/external/',
+           'IPython/platutils_win32',
+           'IPython/frontend/cocoa',
+           'IPython_doctest_plugin',
+           'IPython/Gnuplot',
+           'IPython/Extensions/ipy_',
+           'IPython/Extensions/clearcmd',
+           'IPython/Extensions/PhysicalQIn',
+           'IPython/Extensions/scitedirector',
+           ]
+
+#-----------------------------------------------------------------------------
+# Functions and classes
+#-----------------------------------------------------------------------------
+
 def main():
     """Run the IPython test suite.
     """
@@ -18,36 +54,45 @@ def main():
     warnings.filterwarnings('ignore', 
         'This will be removed soon.  Use IPython.testing.util instead')
 
-    
-    # construct list of plugins, omitting the existing doctest plugin
-    plugins = [IPythonDoctest()]
+    argv = sys.argv + [ 
+                        # Loading ipdoctest causes problems with Twisted.
+                        # I am removing this as a temporary fix to get the 
+                        # test suite back into working shape.  Our nose
+                        # plugin needs to be gone through with a fine
+                        # toothed comb to find what is causing the problem.
+                        # '--with-ipdoctest',
+                        '--doctest-tests','--doctest-extension=txt',
+                        '--detailed-errors',
+                       
+                        # We add --exe because of setuptools' imbecility (it
+                        # blindly does chmod +x on ALL files).  Nose does the
+                        # right thing and it tries to avoid executables,
+                        # setuptools unfortunately forces our hand here.  This
+                        # has been discussed on the distutils list and the
+                        # setuptools devs refuse to fix this problem!
+                        '--exe',
+                        ]
+
+    # Detect if any tests were required by explicitly calling an IPython
+    # submodule or giving a specific path
+    has_tests = False
+    for arg in sys.argv:
+        if 'IPython' in arg or arg.endswith('.py') or \
+           (':' in arg and  '.py' in arg):
+            has_tests = True
+            break
+    # If nothing was specifically requested, test full IPython
+    if not has_tests:
+        argv.append('IPython')
+
+    # Construct list of plugins, omitting the existing doctest plugin.
+    plugins = [IPythonDoctest(EXCLUDE)]
     for p in nose.plugins.builtin.plugins:
         plug = p()
         if plug.name == 'doctest':
             continue
 
-        #print 'adding plugin:',plug.name  # dbg
+        #print '*** adding plugin:',plug.name  # dbg
         plugins.append(plug)
 
-    argv = sys.argv + ['--doctest-tests','--doctest-extension=txt',
-                       '--detailed-errors',
-                       
-                       # We add --exe because of setuptools' imbecility (it
-                       # blindly does chmod +x on ALL files).  Nose does the
-                       # right thing and it tries to avoid executables,
-                       # setuptools unfortunately forces our hand here.  This
-                       # has been discussed on the distutils list and the
-                       # setuptools devs refuse to fix this problem!
-                       '--exe',
-                       ]
-
-    has_ip = False
-    for arg in sys.argv:
-        if 'IPython' in arg:
-            has_ip = True
-            break
-
-    if not has_ip:
-        argv.append('IPython')
-
     TestProgram(argv=argv,plugins=plugins)