Nearly three days, couldn't give you an exact hour, but I'd say somewhere around ~60. I then slept for 18 hours, felt like shit, got sick, not doing that again, lol.
Stayed up a whole night once at a friend's sleepover. We played Halo 2 all night (Bare in mind, this was like 2005) and ate pizza. When it was eight in the morning, everybody just fell asleep.