OpenArena is a 3d game creation engine. It is a rendering system that can be used for more than just games but it is targeted at games. The basic use being create some game media textures models maps and config files for physics and rules.
bjsim is a blackjack simulator, designed to test various basic (noncounting,
total, noncompositional) strategies under various conditions: number of decks,
game rules (double after split, dealer hitting soft 17, etc.).