I had some experience with sleep deprivation, and luckily, they were more funny than tragic, but they tought me a lesson.
Back in the day, I used to attend LAN-parties. Some at friends' houses, some in gyms, and so on. I remember two gaming marathons.
The first was in some old house that wasn't used otherwise. It stood on the grounds of one of the gamers, behind their "real" house. I remember being there playing Team Fortress, TFC and Counter-Strike, with short periods of eating and maybe watching a movie or something, and otherwise living off coke mostly. I was awake about 40 hours straight (we had sleeping arrangements, but sleep's for losers, right?) I remember that somewhere saturday-sunday night, I went to sleep after all, when I noticed that I stuck to the shadows on my way to the toilet. I was sneaking around, crouching, and stuff - and not to be funny. I think if anyone had one of those red dot laser pointers and aimed at the wall in front of me, I'd have jumped off the stairs to safe myself from the sniper.
The other was a commercial affair with 300 people in a sports hall. Again I was awake about 40 hours straight (I didn't really trust people there enough to leave my PC unobserved - my PCs tend to be made up of top-notch pieces, not the cheap ones from a grocery store), browsing the ethernet for nice stuff or playing games. I also remember that I drove home after that. Somewhere around 2am saturday-sunday night. Since there was no city around, only villages, there was practically no traffic except me. And that wasn't a bad thing, I guess. I remember stepping on the brakes because that big white stag on the road. A moment later I realized it was just fog.
After that, I swore to myself never to drive again after 40 hours without sleep (or any other lengthy period of sleepless time).
So, people: Don't think that caffeine will help you. Don't think that you're a tough monkey who won't be affected by "a little lack of sleep". Being awake for that long will play merry hell with your reactions, with your perception, and imposes a -20 penalty to reality checks. Getting back late is better than being late.
