I've done crazy things but this has me beat.  Wish I had one of these in college.
If you don't have plans next weekend, their having the annual event.

The World Championship Punkin Chunkin Association (WCPCA)  ??? is a trademark nonprofit that raises money for scholarships, as well as organizations that benefit youth and the local community. We host a signature pumpkin-launching event each year, fueling innovative engineering and science-based ideas that draw spectators from all over. We believe that Punkin Chunkin cultivates the odd, challenging, and competitive quest for distance that inspires creativity, ingenuity, teamwork, and passion. It is this very dedication that drives teams to compete using science and engineering skills and brings spectators to the gate which allows us to continue our never ending thirst to support our scholarship and charitable programs.
More

http://www.punkinchunkin.com/

Current Records:

Adult Air - 4483.51 ft

Adult Female Air -  3998.83 ft

Adult Centrifugal - 2737.69 ft

Adult Catapult -  2862.28 ft

Adult Trebuchet -  2034.21 ft

Adult Human Power - 1984.37 ft

Catapult
[img width=640 height=381]http://www.yankeesiege.com/Assemblyshow/slideshow024.jpg[/img]

Cannon
[Image Can Not Be Found]