Play those Unreal maps like they were supposed to be played, and try some UT maps with the old weapons. They will stay in there for as long as you keep the button pressed. Works for the grenades as well. One more neat feature is that you can load up three rockets, press your alt-fire, and the autoloading sequence stops, leaving you with a three loaded rocket launcher. The more bounces they take the more damage they inflict when they finally explode.
Rockets have different color lighting.
Fun for some good laughs in tight corridors. UTRA - RocketArena. Not the big one, just a small mutator. Quicken - Increases movement speeds and jumping height. Might - Modifies damage by up to 3x.