I heard a sleep specialist on the radio the other day and he said that what works for many people to reset their circadian rhythms is taking a very very hot bath/shower (hot enough to make you sweat for a while after ou get out) about 3 hours before you want to fall asleep. You raise your core temp, and when your temperature starts to fall in a few hours it mimics the normal circadian temperature drop that happens before sleep for most people. But you have to do it far enough in advance of when you want to sleep or your temp will still be up - so don't take a shower at 9:30 if you want to get to sleep at 11:00.
Other things that have worked for me are valerian root (pills, NOT tea- the stuff smells bad but is a good sedative/muscle relaxant/anti-anxiety medication. Meditation has also worked, as have progressive muscle relaxation exercises.
None of this is as fun as sex, though
