Check out Kiteman's version as well. http://www.instructable,com/id/How-to-Make-a-Desktop-Viking-Catapult-with-a-bonu/
Thanks to everyone who voted for me in the Office Supply Contest!
Here's a video of it firing:
Step 1: What You Need:
- 2 pens
- A plastic bottle cap
- At least 14 elastics
- A craft knife or pair of scissors