Bonus tip for users on Mac OS X: try pressing ctrl+option+command+8. I find that really handy if I'm using my laptop when it's dark and I hit a webpage that's blindingly white.
Oh man I forgot about this! Baddest-Assed. Feature. Ever. I just did it on my girlfriend's machine while she was out of the room. Don't worry, I'll probably revert it for her soon enough.
