I've found a way to stop my head feeling like it's going to burst! It works particularly well whilst I'm sat at my computer, which is good, seeing as free time = sat at computer.

1. Turn off every single light in the room.
2. Close room door.
3. Whack monitor brightness down to 0.
4. Put keyboard backlight on to lowest setting (it's the Logitech G15 "Big Daddy" Gaming Keyboard with the nice blue LEDs behind every key. It looks nice in the dark)
5. Whip out the darkest pair of shades you can find, and out them.

I look like a complete fool, sat in my shades, basking in the dim glow from my monitor and keyboard, but at least my headache is now only a dull throb.