www.cubeengine.com

Singleplayer (2 game modes, savegames) and multiplayer (12 game modes) first person shooter. Over 100 maps, possibility of in-game map editing (even multiplayer). Central server list. Demo recording. Uses OpenGL and SDL. (ZLIB license) [win32, linux and bsd (x86), macosx (ppc), pocketpc (xscale)]