I'll have to suggest Valerian too (I live in a dorm and often use it when I have an early class or something the next day and my neighbors are staying up late.) As far as I know, it's non-addictive and works like a charm. It tastes extremely bad, though, so be sure to mix it with something, or get some pre-blended tea. I usually buy this tea mixture that includes valerian, chamomile, skullcap leaf (relieves stress), and other herbs for flavor. Next time I'm at my local Whole Foods Markets I'll have to get the name for you.
EDIT: Oh, and *lay off caffienated beverages!* I'm a big coffee drinker, and when I'm not getting enough sleep I abstain from anything caffienated for a few days.
Edited, Wed Jan 5 11:13:53 2005 by RognarsDwarvenGrog