A very easy to use and powerful Python interface to the Simple Directmedia Library (SDL) platform independent graphic, audio and input libraries.
There are numerous examples, and the documentation is very good. You'll be surprised at how easy it is to write games or other graphics-intensive programs with it.
You can find it at http://www.pygame.org
Python game programming tutorial using pygame.
Beginning Game Development with Python and Pygame -- A new book discussing game development using Pygame
There is a GUI toolkit based on Pygame called OcempGUI.
See also PythonGames