It's possible to switch to windowed mode while running UT2k4, just press Alt-Enter to toggle back and forth between fullscreen and windowed. The only problem with this is the mouse remains grabbed by the UT2k4 window. To work around that you can add
Code:
Option "AllowDeactivateGrabs" "true"
to the ServerFlags section of your xorg.conf or XF86Config file.
If you dont have a ServerFlags section in your conf file it should look like this
Code:
Section "ServerFlags"
Option "AllowDeactivateGrabs" "true"
EndSection
Once X has been restarted you can use Ctrl-Alt-numpad_divide key to ungrab the mouse
HTH
Mad