Well, there is a drug called Melatonin (or something like that) but it an illegal drug and is hard to get the doctors to give it to you but basically it replaces the chemicals that tell your brain it is time to sleep.
On another note you can try and think of nothing or you can think about something you really like or would like to do and you will fall asleep and dream about that and should not wake.
Also another good remedy is hot sugary milk.
milk + sugar, stir it and then put it in the microwave until it is warm/hot. It works quite well and tastes nice too.