Crush graham crackers into small crumbs using hands or food processor. Stir butter and brown sugar in small bowl until creamy. Spread mixture of butter and brown sugar onto single side of each slice of bread, top butter/sugar mixture with graham crackers. Place marshmallows on inside of bread, add chocolate chips. Spread evenly. Turn oven to 350 degrees. Combine sandwiches and place in over until desired creamy-ness (approximately 2 minutes for golden; 3 minutes for dark). Remove sandwiches from oven and toast/grill on skillet if desired for additional crunch on outer side of sandwich. Slice sandwiches and serve!