I never sleep on friday nights, and usually on saturday nights too. But, I'm always moving during the weekend. As in, if I'm crashing at a friends house, if we get tired then we sneak out and go do shit outside until about 5AM so we're not bored (like walk across town and back). Then come back and ..... hell i don't know, break dance (not really, but we either eat or find something physically active to do like skating in the driveway) until it's semi-daylight and their parents are up, then we all take the public-transit train and go skating like around the main Atlanta area, downtown and suburbia and such. I have been doing this for the past month, but I usually sleep for about an hour on Saturday night as a "refresher".
The bad part is we usually end up doing something stupid* from the lack of sleep and get the cops called on us, who think half of us are high and sweat us until we leave. Yeah, I get searched a lot at school football games for the same reason.
But, the thing is, we don't feel like we haven't slept when we skip a night or two. We feel perfectly normal and all, we're just a little mentally sluggish and have bloodshot eyes.
*(last stupid thing I remember us doing is: we were skating around with sagging pants, half naked with our shirts balled up and stuffed down the front of our pants, in the middle of a slightly busy street, screaming at the cars and grabbing the shirt-ball through the jeans....keep in mind there were about 8 of us)