CannonSmash, a table tennis simulation game
CannonSmash is a funny 3D table tennis game. It takes a while to get your hand at ease with the mouse+keyboard manipulations. But once you're used to the technique, you can feel like playing a real game. It is playable against the computer or through a network.
Since csmash relies on OpenGL-compatible rendering, it is best experienced with a 3D accelerator card, although software rendering in wireframe mode should be sustainable.