This is the "Industrial Grade Human Powered Paper Rocket Launcher" in use at the LEAF festival in Black Mountain, North Carolina.
Rockets are made from a half sheet of 8.5x11 "card stock" paper and can be launched many times. Rockets that are built well will fly 50 yards!
In this video two older "kids" launch their paper rockets with the goal of landing them inside the tennis courts. And, they did it!
Download build-it-yourself plans at www.TomHeck.com