If you have a graphics control, try turning down the gamma 
i have the nVIDIA control panel, and after Disconnecting from tremulous, the gamma is set at 1.0. the lowest it will go is .50, which is still way too bright.
Play tremulous with standard gamma and it shouldn't effect you. 
same as Aviator, i have to play with gamma turned up to 1.8 to be able to see anything.
so is this a tremulous bug maybe? quitting tremulous normally, gamma is returned to the normal value. "Disconnecting" from tremulous, the gamma value is not restored and desktop environment is too bright until the computer is rebooted..