I've pulled far too many all nighters in my day.
During college, I had many cases where I had a program to write and I left it till the last minute. In those cases, it was a mix of caffeine, marijuana and ritalin (dont worry, I have a perscription) keeping me awake.
After college I went thru a massive World of Warcraft addiction (which I'm still recovering from). Then I didnt need anything to keep me awake, the pure stimulation of playing could keep me going for days. I once woke up on a friday at 12pm and didnt stop playing (other than to eat/piss) until late sunday night. Funny thing is I remember virtually nothing past noon saturday, its like the brain cant store the memories if you dont get sleep.
And of course there's been the odd partying all nighter... last saturday I didnt crash until about 6 or 7 am when the party died out. Usually in those cases I ended up sleeping half the next day, its rare that I can make it thru the second day and not go to bed until a normal time.