I've stayed up all night many, many times, but often I end up falling asleep in the afternoon of the next day, so it kind of lessens the blow while still messing up my sleep patterns .

For me, the worst time for falling asleep is about 4:30-5:30. Once I get past 5:30, I start getting kind of giddy and I perk up again, and so I can stay up until noon or so, or all day if I have to...

And no, I've never really taken anything to keep me awake, I just tend to stay up late all the time, so I'm used to it (it's 3:45am right now, in fact )

Staying up all night is fun a lot of the time, but it's offset a bit by the next day being kind of a writeoff because either I'm sleeping or just pretty out of it.