SolitaireCryptoDemo A visual demonstration of the steps involved in generating a keystream using Bruce Schneier's Solitaire encryption algorithm.
JointedLine A simple exmaple how draw and modify jointed lines.
LinePointDistance Simple implementation of a Point to Line distance algorithm. The algorithm also calculates the location of the closest point on the line.
Rayforge Rayforge is a simple and fast (for python) raycaster. It will never be as advanced as the Doom engine, but this is just to show how raycasting is done.
The Khan Simulation Physics based fighter (proof of concept), character editor, and open source engine. Uses pygame, pyopengl, pyode, pygtk, twistedmatrix.
3d engine This is an attempt of writing a 3d engine. It is not usable yet but looks promising. With a bit of help with the math it would be a great tool for develloping ego-shooter like games.