Nexuiz is a free, cross platform, FPS (first person shooter) distributed under GNU General Public License by Alientrap Software. It started back in May 31 2005 with version 1.0 using DarkPlaces, a significanlty modified Quake engine. The current version, 2.3, was released on May 31, 2007. Available for Linux, Mac and Windows.
Several notable features of the game include
* ability to multiplay up to 64 players
* ability to generate bots for practice sessions
* dynamic lighting system similar to Doom 3
Get the game here... http://www.alientrap.org/nexuiz/
From: Gamesuy