Evenly break each of the three graham crackers in half. This is easiest to do with a sharp serrated knife - use the knife to score the graham crackers and then break them in half.
Set aside 5 graham cracker halves. Cut the 6th in half again and discard one piece. Cut the other piece into a triangle for a roof support.
Place the chocolate chips in a baggie and melt them in the microwave (30 seconds at a time until melted). Snip a corner off the bag and use it to pipe chocolate across the bottom of the roof support.
Place the roof support at the top of a graham cracker half, and lay down on a flat surface.
Use melted chocolate to "glue" two more graham cracker halves on to form a roof. It can be helpful to use a cup to rest the first roof piece against until the second roof piece is in place (see video).
Use melted chocolate to "glue" two more graham cracker halves on as walls.
Chill the house for 15-20 minutes until the chocolate is hard (can be placed in the freezer for faster chilling). Decorate as desired.