Lately when I wake up in the middle of the night and find it difficult to get back to sleep, I realize that I have a song stuck in my head, too. It's not always the same one, but it is always nearly impossible to get rid of, and it definitely contributes to my sleeplessness. In researching this phenomena, I've found that it is called an earworm. No one knows why it happens, and there is no definitive cure. The number one piece of advice offered is to tolerate those haunting melodies until they fade off on their own. Um. No.
Years ago I had a friend who swore that singing Sister Christian by Night Ranger would knock any song out of your head, but even motorin' through that little ditty hasn't helped. Focused breathing, meditation, prayer, none of them help to disrupt the phonological loop bludgeoning my brain. Today I read that music on a non-western scale, such as Indonesian Gamelan or even Gregorian chanting, might work, and I intend to put some on my iPod right now and leave it next to my bed tonight.