Depends on why you would want to. If there are other people around as well. There are other factors that contribute. If you got a good night's rest, stress, etc.. I hear caffeine helps keep people awake (for a while). Supposedly it works but if you don't continue to get more your energy will take a skydive. Doesn't too much for me though. You could try eating something spicy when you start getting tired. Basically do anything that would make you more alert.

easiest way I have found is to do something you like to do.
When your having fun, it's much easier to star up for long, long periods of time.

go outside in the middle of the night, its more fun with friends though. but if your alone devote your entire night to something. unless your planning to stay up on halloween, then egg some houses :D

booze
or 3 big bottles of coca cola
but hey i'm a casffeine junkie
PS how did i get on to your page?

Dont do anything boring, keep yourself thinking.