diff -r 815b88454e3e Lib/test/test_importlib/builtin/test_loader.py
--- a/Lib/test/test_importlib/builtin/test_loader.py	Fri Aug 31 17:14:31 2012 -0400
+++ b/Lib/test/test_importlib/builtin/test_loader.py	Sat Sep 01 02:29:00 2012 +0100
@@ -92,7 +92,6 @@
             method = getattr(machinery.BuiltinImporter, meth_name)
         with self.assertRaises(ImportError) as cm:
             method(builtin_util.BAD_NAME)
-        self.assertRaises(builtin_util.BAD_NAME)
 
 
 
diff -r 815b88454e3e Lib/unittest/case.py
--- a/Lib/unittest/case.py	Fri Aug 31 17:14:31 2012 -0400
+++ b/Lib/unittest/case.py	Sat Sep 01 02:29:00 2012 +0100
@@ -99,12 +99,24 @@
         raise _UnexpectedSuccess
     return wrapper
 
+def _ensure_is_exception_type(e):
+    if not isinstance(e, type) or not issubclass(e, BaseException):
+        raise TypeError('assertRaises arg 1 must be an exception type '
+                        'or tuple of exception types')
+
 
 class _AssertRaisesBaseContext(object):
 
     def __init__(self, expected, test_case, callable_obj=None,
                  expected_regex=None):
         self.expected = expected
+
+        if type(expected) is tuple:
+            for e in expected:
+                _ensure_is_exception_type(e)
+        else:
+            _ensure_is_exception_type(expected)
+
         self.test_case = test_case
         if callable_obj is not None:
             try:
diff -r 815b88454e3e Lib/unittest/test/test_case.py
--- a/Lib/unittest/test/test_case.py	Fri Aug 31 17:14:31 2012 -0400
+++ b/Lib/unittest/test/test_case.py	Sat Sep 01 02:29:00 2012 +0100
@@ -1027,6 +1027,31 @@
         self.assertIsInstance(e, ExceptionMock)
         self.assertEqual(e.args[0], v)
 
+    def testAssertRaisesNoExceptionType(self):
+        try:
+            self.assertRaises(1)
+            self.fail("Expected TypeError")
+        except TypeError:
+            pass
+
+        try:
+            self.assertRaises(object)
+            self.fail("Expected TypeError")
+        except TypeError:
+            pass
+
+        try:
+            self.assertRaises((TypeError, 1))
+            self.fail("Expected TypeError")
+        except TypeError:
+            pass
+
+        try:
+            self.assertRaises((object, 1))
+            self.fail("Expected TypeError")
+        except TypeError:
+            pass
+
     def testAssertWarnsCallable(self):
         def _runtime_warn():
             warnings.warn("foo", RuntimeWarning)
diff -r 815b88454e3e Misc/ACKS
--- a/Misc/ACKS	Fri Aug 31 17:14:31 2012 -0400
+++ b/Misc/ACKS	Sat Sep 01 02:29:00 2012 +0100
@@ -1102,6 +1102,7 @@
 Frank Visser
 Johannes Vogel
 Sjoerd de Vries
+Daniel Wagner-Hall
 Niki W. Waibel
 Wojtek Walczak
 Charles Waldman