I can make mine go away temporarily (as in a minute or so) by sticking my fingers in my ears and jiggling them around to make a lot of noise for 10 seconds. I suspect it's just the contrast, but it is really nice to have something resembling real silence.

A few years back I got a bad wax buildup in one ear and stopped hearing anything. After they took the wax out, my ear was hypersensitive for a day or so. I heard every little rustle, shifting in my chair, even fabric moving when I moved my arm.