I finished making optimizations to the sprite module. The new sprite.py has been uploaded to the Subversion repository. I am pleased to announce that on my Mac with Python 2.5, sprite_test.py now runs in 0.038 seconds rather than 0.076 seconds, and on my PC with Python 3.1, sprite_test.py now runs in 0.016 seconds rather than 0.031 seconds. If I have inadvertently broken your code or made it slower, let me know and I'll undo the optimization that doesn't work for you.
Jason