Some Quia games and activities on Simple Machines
A. Amusement Park Physics
http://www.learner.org/interactives/parkphysics/
B. Physics for Kids - take quizzes on Friction, Forces, and Motion
C. Simple Machine Laboratory
http://aspire.cosmic-ray.org/labs/machine/
D. Simple Machine Activities from Chicago Museum of Science and Industry
http://www.msichicago.org/online-science/simple-machines/activities/simple-machines/
a. Quiz on Forces
http://neok12.com/quiz/Q7VQM96T
b. Quiz on Simple Machines
http://www.neok12.com/quiz/KLJJ8MRL
1. Rags to Riches game
http://www.quia.com/rr/311921.html
2. Pop ups learning activity
http://www.quia.com/pop/431074.html
3. Quiz Quiz on Simple Machines
http://www.quia.com/quiz/2501438.html
4. Quiz on Forces and Motion
http://www.quia.com/cz/346286.html
5. Quiz on simple machines/forces
http://www.quia.com/quiz/2462317.html
6. Another quiz activity on quia
http://www.quia.com/quiz/2462318.html
7. Quia column matching - play several times!
http://www.quia.com/cm/42409.html
8. Simple Machine Activities
http://www.cosi.org/files/Flash/simpMach/sm1.swf
9. Leonardo's Machines!
http://www.mos.org/sln/Leonardo/LeosMysteriousMachinery.html