Actually, the best way is any form of exercise.
No, not really. It gets your heart pumping and etc. I think it does the opposite of making you fall asleep. Plus where's he going to exercise?
Just keep your eyes closed. Take a deep breath in and out, let yourself sink into the mattress and relax all muscles in the body.
If all else fails, bust out your mp3 player and play your favorite music on the lowest possible volume.