I used to make these as a kid.  They're great when you have a craving for smores but it's 20 below outside.  Break a graham cracker in half so you have two squares. Coat one side of both squares with peanut butter. Add a few chocolate chips and mini-marshmallows to one square, peanut-butter-side up.  Put the other graham cracker square on top, peanut-butter-side down, so that you've made a little smore sandwich.  Wrap in a paper towel and put it in the microwave for 10-20 seconds.