I usually sleep around 12 and get up around 6:30 or 6. In the summer it was a lot worse though. I would sleep around 2 or 3 or later everyday. Some nights I wouldn't get any sleep and end up sleeping in the afternoon.
I am definitely a night owl. Unless I am sick or only had a few hours of sleep the night before, I cannot get to bed before midnight. Even during class days I normally fall asleep around 1 or 2 o'clock in the morning and wake up 6 hours later. I just can't sleep early.
I'm a day person and a night person. I don't usually sleep for more than 6 hours if I don't need to. I've survived weeks on just an hour a night and I wasn't bothered by it. I just give myself 6 so I don't feel pressured to fall asleep.