Backyard Ballistics, by William Gurstelle
kaBOOM!
"When you were a child, people told you not to play with matches for a good reason-they can be dangerous!..."
Having said that, this book goes on to show you how to (safely) construct things like a potato cannon, a tennis ball mortar, carbide cannon and ballistic pendulum, among many others. It's a whole lot of fun!
(The back cover)
