this works for me every night, although it would be kinda hard if you dont have an imagination...
i write a story in my head while im trying to fall asleep. you know, with heros, bad guys, fair maidens being held hostage by a dragon or some such thing...i usually fall asleep before the hero even gets into town.
it works just as well if you make a story about a bad guy too.
aw hell, make the story from the maidens point of view...for a little twist, make the dragon a cricket or something.