I once saw a lesson plan done on "Spin Art" by using...
(O.K. don't laugh until you 've tried it !!) a salad spinner.
You know the things that they sell for $4.99 to dry out your lettuce after you've washed it. A resourceful Art teacher solution as opposed to the alternative buying of a kit from a catalog. I believe that you have to cut the paper to a special size to fit the spinner but it was a great way to emphasize that art can be created by chance.
Hope it helps ! :) Chris