Depends on the days. With school, usually 11:30-12:30, on the weekend or break, I can stay up for extended amounts of time. usually 4-5am if Im feeling up for it.
During the summer, however, I usually stay awake for 24+ hours, sleep during the middle part of the day, then start it over again. If I drink coffee, I tend to last for the rest of the day, but thats if i drink coffee all day.