Catapults
Ms. Brown
Catapult Crazy! Everything About Catapults
This site provides basic instructions for many different types of catapults. Scroll down to bypass the advertisements.
This site has pictures of a catapult competition. There are many
interesting creations that might inspire your design.
This is a retail site that sells catapult kits. It includes instructions
for one type of catapult.
HubPages: How to Build a Catapult
This site provides instructions for a clothes pin catapult.
Google Images - How to Build Catapults
This link provides catapult images gathered from a google search.