Urban Terror is a realism based total conversion mod for Quake III Arena which
no longer requires this game to be played. It only uses its engine, which is
open sourced through the GPL and may be distributed freely. Urban Terror plays
in about the same setting as Counter Strike, but is less focused on realism
and plays much faster, which among other things, is caused by the ability to
strafe jump, which combined with wall jumping can lead to very quick movement
and nice jumps. Urban Terror has 7 game modes, 25 maps and 15 weapons.

This port installs the modified ioquake3 engine for Urban Terror called
ioUrbanTerror, and depends on the data, resulting in a playable game.

WWW: http://ftp.snt.utwente.nl/pub/games/urbanterror/iourbanterror/source/