How about the wooden produce box ends that we used to put into an “L” shape and cut two edges off the right angle sides then put a nail in the front and attach a rubber band and pull it over the lip at the right agle. Then put a little square of light cardboard between the rubber band and push the rubber band off with the thumb and watch the missle go flying. It had quite a force and a bit of a sting if it hit you. A bit more creative than the guns the kids use today.