You will need a pen/pencil, a binder clip, and a rubber band.
Step 2: Assembly
First fold the the binder clip to make the clips on the back. Then get the rubber band and twist it and put the sides together on one finger. Repeat this step once. Next put the band on the clip. After that you will need to put the pen/pencil through the band.
Step 3: Time To Launch
Finally you can take some thing to launch and launch it! Pull back on one the clips with the item on it and let go.