Place (an equal amount of banana slices) half of a sliced banana, some chocolate chips, and marshmallows into a piece of heavy foil formed into a boat shape (an oven proof casserole dish could also be used). Turn the grill down to low heat, place the boat on the warming rack, and heat for about 10 to 15 minutes, until the marshmallows melt. Add a scoop of ice cream for a desert sure to please all the kids!