Sauerbraten / Cube 2 Game Engine. You’ve got a computer game idea burning in your breast. You’ve been looking for the perfect engine to use to build it. So here you go, young person. Download and enjoy.
Much like the original Cube, the aim of this game is not necessarily to produce the most features & eyecandy possible, but rather to allow map/geometry editing to be done dynamically in-game, to create fun gameplay and an elegant engine. The engine supporting the game is entirely original in code & design, and its code is Open Source (ZLIB license, read the docs for more on how you can use the engine). In addition to the FPS game which is in a very playable state, the engine is being used for an RPG which is in the preproduction phase.