just try drinking a warm glass of milk. it has tryptaphen (sp?) in it and works like a charm. about 20 minutes or so prior to bedtime, and try not to go to sleep with a full stomach (i.e. don't eat right before bedtime). And now for the perverbial "Got Milk" plug...
oh, yeah...i forgot about tryptophan. simply eat about a half-pound of roasted turkey. throw in some dressing, gravy, sweet potatoes, and a hot buttered roll and turn on the television. this has worked wonders in my family for years -- usually sometime in late november.