I usually go to bed somewhere between 9 PM and 4 AM, with a marked preference for a time between 10 PM and 2 AM. I'm in a bit of a special case right now, because I've had all of an hour's sleep in the last two days -- I was last in my bed at 10:45 on Tuesday morning, and it's 2:53 Thursday morning now. The hour of sleep involved conking out in a chair while watching my roommate play Fallout 3.