I'm in high school, and I try to see how long I can stay awake fairly frequently. I've heard it's bad for growth and such, but I'm already fairly tall, so whatever.
The longest I've ever gone was 48 hours, although I've been there at least three times. I usually stop because the idea of going another day (and it doesn't feel "worth it" unless I can say it's been three days) is too daunting. Interestingly enough, I don't get quite as fuzzed up as some of you seem to. I function perfectly fine, my eyes just burn like hell.
Fun and relevant story. I was napping on a Saturday and woke up at 3:00 pm. I decided to see how long I could stay up. I proceeded to stay awake through the following Sunday, and went to school on Monday. My last class of the day was history, and I had a final that day. Mind, I get to history at 1:00 pm. So, having gone ~46 hours without sleep, I took my history final. I went home and crashed.
I later got my results back and found out I got a perfect on that final. I felt like such a badass.
I think I'll try for that elusive 3-day again, starting today. Woo!