Seeing as I've been playing a lot of UT2004 Instagib at work lately (not during work hours! Don't hate me!) I figured one last mutator for Unreal Engine 2 couldn't go astray.
It's called 'InstaJump' and it does a whole bunch of cool stuff. The main features are shockjumping, which is a bit like rocket jumping I guess, and completely customisable beam colouring because I got carried away with it.
More info, screenshots and a download link are here.