From LinuxGames:

That tirelessly coding fairy godmother of the Linux gaming community, Ryan "icculus" Gordon, has posted news that a 64-bit native version of the UT2004 demo (see our previous post) for AMD's AMD64 line of processors is now available. This package includes both the client and the dedciated server. Ryan cautions people to consider several factors when evaluating the AMD64 build. The compilers/drivers on this architecture aren't nearly as mature as you might be used to on a 32-bit system, so don't be too critical about performance just yet. If you don't have an Opteron, Athlon64, or Athlon FX processor then this build is useless to you. If you don't have a 64-bit operating system, then this build is useless to you. And, finally, there are reports of system lockups and reboots when running this binary: you have been warned. In short, you probably shouldn't be running this on your company's mission-critical webserver.

Read the full thing here

I've been waiting for this since I built nefarious... it better be good :)