Building a Trebuchet
Link to the NOVA companion web site for the video on Trebuchets.
You can also Destroy
the Castle using a Trebuchet.
Global Spec Trebuchet Challenge: A game which allows you to change the trebuchet design, including the mass of the projectile and the counterweight and the launch angle, to maximize distance, accuracy and power.
Trebuchet.com has plans and kits for sale, but it also has pictures of model Trebuchets and other types of catapults, and a Trebuchet simulator.
Full size reproduction Trebuchets at Caerphilly Castle, Wales.