Alien Arena is a fast paced, furious frag fest with arenas ranging from the small, to the massive. (GPL)

Blood Frontier is a single-player and multi-player first-person shooter game, built as a total conversion of Cube Engine 2 (Sauerbraten). (GPL)

BZFlag is a free online multiplayer cross-platform open source 3D tank battle game. (LGPL)

Nexuiz is a 3d deathmatch game project, created online by a team of developers called Alientrap. (GPL)

OpenArena is an open-source content package for Quake III Arena licensed under the GPL, effectively creating a free stand-alone game. (GPL)

Sauerbraten (a.k.a. Cube 2) is a free multiplayer and singleplayer first person shooter, built as a major redesign of the Cube FPS. (GPL)

Tremulous is a free, open source game that blends a team based FPS with elements of an RTS. (GPL)