diff --git a/contextlib2.py b/contextlib2.py
index f99bbee..f02a381 100644
--- a/contextlib2.py
+++ b/contextlib2.py
@@ -141,13 +141,14 @@ class closing(object):
         self.thing.close()
 
 
+# Inspired by discussions on http://bugs.python.org/issue13585
 class ContextStack(object):
-    """Context for programmatic management of resource cleanup
+    """Context manager for programmatic management of resource cleanup
     
     For example:
     
         with ContextStack() as stack:
-            files = [stack.enter_context(fname) for fname in filenames]
+            files = [stack.enter_context(open(fname)) for fname in filenames]
             # All opened files will automatically be closed at the end of
             # the with statement, even if attempts to open files later
             # in the list throw an exception
diff --git a/docs/index.rst b/docs/index.rst
index 93192aa..e4be3a3 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -199,7 +199,7 @@ API Reference
    statement as follows::
 
       with ContextStack() as stack:
-          files = [stack.enter_context(fname) for fname in filenames]
+          files = [stack.enter_context(open(fname)) for fname in filenames]
           # All opened files will automatically be closed at the end of
           # the with statement, even if attempts to open files later
           # in the list throw an exception