Paintball2 - Free First-Person Shooter For Windows and Linux

Paintball2 is a fast-paced first-person game with capture the flag, elimination, siege, and deathmatch (free-for-all) styles of gameplay.

Paintball 2 was originally a Quake2 mod. Now that Quake2 has been released under the GPL, Paintball2 has become a complete standalone game with an enhanced, open-sourced engine.