Project Page: http://sourceforge.net/projects/fquake
Home Page: http://fquake.sourceforge.net/
Hexen II: Hammer of ThyrionfQuake is a comprehensive online QuakeWorld installer with anything one could need to play online, and beyond. fQuake is based on the idea of eQuake where users get everything they need in one package, only this time it is 100% legal, and open-source.
Project: http://sourceforge.net/projects/uhexen2
Home: http://uhexen2.sourceforge.net/
BZFlag - Multiplayer 3D Tank GameHammer of Thyrion is a port of Raven's Hexen2 source code and is based on the original Linux Hexen II project, Anvil of Thyrion. HoT includes many bugfixes, improved sound and video modes, opengl improvements and documentation among many others.
Project: http://sourceforge.net/projects/bzflag
Home: http://bzflag.org/
ActionCubeOpenSource OpenGL Multiplayer Multiplatform Battle Zone capture the Flag. 3D first person Tank Simulation.
Project Page: http://sourceforge.net/projects/actiongame
Home Page: http://action.cubers.net/
ActionCube is a total conversion of Wouter van Oortmerssen´s FPS called Cube. Set in a realistic looking environment, as far as that´s possible with this engine, while gameplay stays FAST and arcade. This game is all about team oriented multiplayer fun
other:
Crystal Space 3D SDK
Project: http://sourceforge.net/projects/crystal
Home: http://www.crystalspace3d.org/
Crystal Space is an Open Source 3D SDK for Unix, Windows, MacOS/X. It renders with OpenGL or software and features curved surfaces, volumetric fog, dynamic colored lighting, terrain engine, LOD, procedural textures, portals, etc.
