"As most of you probably know, id software released the Quake3 engine in summer 2005 under the terms of the GPL, nearly two years ago. Ever wonder what came out of it? Even though the engine is eight years old, just recently two independent projects have released fully featured multiplayers games, weighing in with downloads of about 550 megabytes each. Urban Terror and World of Padman, formerly modifications that required you to have the original Quake III Arena game, can now be played independently as stand-alone versions. Urban Terror combines realistic environments and weaponry with movement similar to Quake3. World of Padman on the other hand is a colorful shooter in comic style giving you fun weapons like water balloons and water pistols to shoot with. Last but not least there is Tremulous, a first person shooter with added real time strategy elements which has been out for quite some time now. Interesting to note, its game data is licensed under a CC license. All three games use an improved Quake3 engine from ioquake3, which has cleaned up the Quake3 source code since its release and made many improvements like OpenAL, Vorbis and SDL support, and thus are available for Windows, Linux and MacOSX. If you are willing to compile the engine yourself you can get support for even more platforms like Solaris or *BSD."