Hypnosis?
I did the research project back in high school about sleep disorders, including insomnia, and I found something kinda cool. It's like self-hypnosis. Works 100% of the time for me... usually I don't even get all the way through.
Before you start, make sure all distractions are out of the way... any light is off, anything that makes noise has been silenced, that sort of thing.
First, you lie down in the yoga position "The Corpse," I think it's called that anyway, where you're on your back with your arms at your sides and your legs straight. Make sure you're comfortable.
Then, stare really hard at any arbitrary point on the ceiling... I use a small yet visible scratch in the ceiling. It's important that, while you can blink, not to close your eyes or look away from that spot. Don't fight your eyes closing, as they'll drift closed on their own time.
Next, start breathing. Breath in through the nose for a count of 8, and out the mouth for a count of 8. Concentrate on the numbers, the breathing. This will help clear your mind and lower your heart rate (This is where I usually pass out ^^).
Now, while still breathing / counting, focus on relaxing every part of your body moving up from the feet, so feet, then lower legs, then upper, etc., until you've completely relaxed your body.
Once relaxed, imagine that you're somewhere really relaxing, like a deserted island or some other really tranquil place. Anywhere peaceful place will do, just so long as you're able to visualize it. My mind is usually pretty focused by now, what with the breathing, so I can imagine some cool stuff. Anyway, keep the breathing rhythm going as you do this... your mind should be on nothing but whatever scene you visualized and the slow, steady breathing.
So yeah. The key to this technique is patience. It's meant to be taken at a leisurely pace, so take your time. This probably won't work for everyone, but I've gotten nothing but awesome, hard sleep doing this. Good for before any events where you need to be rested, i.e exams, whatever. Beats drugging yourself, anyway.
