47 hours is my record, it got me a (minor) nickname in high school of "Two Nighter".

That was just me gaming like crazy and seeing how long I could keep it up for, it wasn't do to any actual work, assignments, events, training etc.
Then again... I did once do a 25 page essay in 6 hours straight, I've never been someone to have to alter my sleep schedule on account of assignments.

But I do it all the time when there's nothing like school to wake up for and just want to play games really late.