How can I decrease brightness in Blackbox/X windows?
 

The question says it all. Even with my moniter set at it's lowest brightness setting my display is really bright. Is there some setting in the blackbox or X config files that can change the gamma or something? I'll admit, I don't have the highest quality moniter (max 75hz refresh, 1024x768 res -- borrowed from a friend), but I'd still like to do something if i can.