Crossfire is a multi-player graphical arcade and adventure game made for X. It has certain flavours from other games, especially Gauntlet and the rogue-like games (Nethack, Moria, Angband, and Ragnarok). Any number of players can move around in their own window, finding and using items and battling monsters. They can choose to cooperate or compete in the same world.
game control program helps you administrate gameservers (it's written for Q1 and Q3, but works for others). It is highly modular and therefore extensible. With the current modules, it can start/stop servers, create and rotate logfiles, allow remote administration via telnet, and kick misbehaving players automagically (according to a rule set).