My record time for staying up was roughly...36 hours. By that time my body consisted of mostly energy drinks (not for the caffiene but because I wasn't in the mood for tea) and chips (I get REALLY hungry at night). But I've noticed that some things start happening in a particular timeframe.
From 2am onwards: Any music I have playing on WMP becomes a slight buzzing sound, until I turn up the volume or pick a new song. Along with that, I might start getting a little bit hungry and paranoid that my parents will come up to check on me any minute (creaky floorboards happen to be my most feared sound at night).
3am onwards: Any game I happen to be playing is a bit like watching a movie. I'm not really doing anything, but the main character is blasting everyone with a shotgun/machine gun and I clench my teeth slightly any time I turn a corner...damn trigen.
4am onwards: Whenever I have to leave for the toilet, I start hallucinating with things from horror movies and screamers appearing in the shadows, and I start hearing whispers and such.
6am onwards: All of the above, yet I keep giggling and laughing at anything. (Once, I almost choked on a toothbrush and couldn't stop laughing for 10 minutes).
