For the record, the mod Alien Swarm kicks total ass. It's extremely difficult in places and requires a lot of synchronized, good teamwork. If you've seen the Alien movies, you'll love it especially much.

Download it here for UT2004: http://www.blackcatgames.com/swarm/download

(There will soon be a new version of Alien Swarm for HL2 as well.)

"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram