Do you sleep with the light(s) on or off?

I sleep in absolutely anything. Any surface, any level of sound, any amount of light, etc. Doesn't matter. If I'm tired, I will fall asleep.

That said, if I actually choose to go to sleep of my own free will, I turn the lights off first. Naturally.

THIS.

Although I can sleep anywhere at any time, i prefer darkness. I am an INCREDIBLY light sleeper and will wake up to a housemate's alarm clock and/or the rising sun. That said, i prefer the door closed, but with a roommate, the room would get stale and stuffy (which, IMO is worse than having light in your room while sleeping), so i leave the door open. Over the school year, i can sleep with a small amount of light and a small amount of noise, but when i get home, complete and utter darkness.