Build a square frame by gluing the ends of four craft sticks together. Lay eight more craft sticks parallel to the sides across the open space and glue them to the frame. Alternatively, you can use a simple wooden block as the catapult platform.
Stack the two clothespins on top of one another. Glue them together facing the same direction.
Twist a rubber band several times around the top piece of the upper clothes pin (the end that you push on to open the clothespin). Slide a jumbo craft stick under the bands and glue a plastic bottle cap to the opposite end. Let the glue dry thoroughly.
Place a small object such as raisins, marshmallows, cotton balls or paper balls into the cup on the craft stick lever. Depress the clothespins to fully open the pinching ends and let go to watch your projectile fly.