I have a friend who suffers from insomnia. It's something I experience myself, but she has it much worse than me.
I have another friend, from India, who likes to share a breathing technique that helps people overcome anxiety, depression and...insomnia (among other conditions). Today I got my two friends together, and joined in myself with a "counting breaths" class.
It's incredibly simple. Bend each of your fingers in turn into your palm. Breath in and out three times per finger, counting each breath. Carry on until you fall asleep.
That's it.
Basically it's just a means of blocking out all those thoughts and/or worries that tend to crowd in and whirl around when you can't sleep. Apparently it's extraordinarily successful.
My insomniac friend and I are going to try it, and we'll report back to our instructor next week. Of course, I'll report back here, too. Meanwhile, if you're having trouble sleeping, or you're worrying about something, or you just would like to try this very basic form of meditation for yourself, there are more details
here.