The mod scene for Unreal Tournament is alive and well. Witness Mayday a fledgling mod for UT, a self-described futuristic war sim. Here's a little more:
Mayday is a modification for unreal tournament. It is a futuristic war sim set in the year 2438. After many troubles and problems, war has broken out on earth again. Several years into the war however, earth was placed under threat as an alien civilisation started to attack earth. The many nations on earth joined up to be rid of the alien menace and the war still continues. In Mayday, you will help fight the war by either protecting your homeland earth, as one of the many soldiers fighting or try and take over earth as the alien menace. Mayday will feature new classes, weapons and game types for Unreal Tournament.