I show how to make a simple pen gun that uses a rubber band and can shoot airsoft bb's as well as other things. I use two pens, a mechanical pencil and an elastic band, but it can also be made with simply one mechanical pencil and an elastic band. I used two pens to make it so I can fit projectiles larger then bb's. It shoots hard enough to break two layers of paper and stick tacks into a cork board. Not the most accurate but if you are shooting at large targets you will probably hit them the majority of the time. A simple and fun little toy gun.