Spin Art Machines have been around for a while and I have seen them at craft shows for years.
You could buy a Spin Art machine for anywhere from $12 to $282 depending on the size and quality of the machine.
If you have a spare box fan and some card board, you can make your own at home for pennies on the dollar!
Step 1: Acquire Supplies
1. Box Fan - any size (16", 20", etc) : http://www.walmart.com/ip/Galaxy-20-Box-Fan-4733/10553592?findingMethod=rr
2. Corrugated Cardboard - I used the cardboard from a Husky air compressor cardboard box. Should be stiff
3. Chipboard - The size of the chipboard sheets depends on the size of the cardboard base cutout above. Use small chipboard sheets from Michaels or other craft store.
4. Push pins - Holds the chip board during spinning to the cardboard
5. Acrylic Paint
6. Mustard and / or Plastic Ketchup Bottles - Used to squirt paint onto spinning canvas (http://www.google.com/products/catalog?q=ketchup+bottles&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&tbm=shop&cid=2210169627730432471&sa=X&ei=DvW8T5D3HoOpgweSx-H3Dg&ved=0COcBEPMCMAA)
7. Drywall screws - for attaching cardboard base to fan
8. Phillips screwdriver or Drill with phillips drill bit
9. Large cardboard box - to catch overspray
Step 2: Remove Front and Back Fan Grills
Remove the front and back fan grills using a small phillips screwdriver and discard into trash.
Step 3: Cut Fan Blades
Using a dremel or other similar tool, slice existing fan blades from unit. Discard blades into trash. It's ok if you have a little excess "stump" from the blades.
Step 4: Cut 8" X 8" Cardboard Base
Using corrugated cardboard, cut approximately 8" x 8" and ensure it fits on top of white, circular disc in fan.
Step 5: Attach Cardboard Base to Fan
Using at least 4 drywall screws, attach cardboard base to fan. Keep in mind you may have to use trial / error here. I noticed that in some spots, I could not drill into because it prevented the fan from spinning. Back out screw and try a new location.
Step 6: Execute 15 Minute Spin Test
After I was sure the cardboard was firmly attached, I let the fan run on the highest setting to make sure the cardboard did not spin off. If you feel it will spin off, then add more drywall screws.