This should teach your co-workers who's boss. Spend half an hour making it, then have hours of fun hassling your co-workers or target shooting. Mine shot a pencil eraser about 30 feet easily.
Check out Kiteman's version as well. http://www.instructables.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: