I have a few favorite books that I have read so many times I can pick them up, open them anywhere, and read for a little while. I usually tryo to pick up one of those when I can't sleep.

If I still can't sleep afte reading for a few minutes, I try this:

Start with your toes, and mentally tell each part of your body to fall asleep. I picture each part, as I tell it to fall asleep, getting loose and limp and warm. Generally, by the time I get up to my shoulders, I fall asleep.