Introducing the 6 Simple Machines
Simple Machines Made Simple - Lots of examples, short movies (no sound)
Simple Machines Learning Site - Good examples of real world applications. Includes a quiz
Inventor's Toolbox - From the Museum of Science in Boston
Rube Goldberg Games and Site
Rube Goldberg Official Site - http://www.rubegoldberg.com/
Goldburger to Go - http://pbskids.org/zoom/games/goldburgertogo/rubegame.html
Tom’s Trap-o-matic - http://www.infinitecat.com/games/tom-n-jerry.html