Allison blogged (is that a verb?) about having occasional challenges falling asleep. One of the residents (MD) where I work taught me a breathing technique he called the Rule of 5. I don't have a link but here is the idea.
5 times a day - take 5 breaths in the following pattern - breath in while counting to 5 - hold the breath for 5 counts - then breath out while counting to 5. This exercise helps with stress and might help with those nights of insomnia so you can get the sleep you need!
Sleep well.