Your post reminds me of seven year old twin boys we had in the hospital where I used to work. They had somehow found some gun powder in the attic of their grandmother's house. They took it outside and played the Road Runner cartoon, placing two long lines, and then lighting it with kitchen matches.
They were hurting for a couple of days, but not seriously hurt.
Take an old washing machine or dryer apart - doesn't matter what the machine is, as long as it has a squirrel-cage cylindrical fan on the motor shaft.
Stand the motor on end, with fan cage up. Use sticks or something to prop it up.
Build protective blockhouse out of large cardboard box. Cut a hole in it and cover with layers of heavy Saran Wrap so you can see out.
Run plug from motor to blockhouse.
Fill fan cage with very ripe plums, figs, apples - any soft fruit. Remove pits if possible for better throughput.
Take up stations inside blockhouse, plug in motor and watch it whirl.
Spend the rest of the weekend scrubbing purple-and-brown stripe off house, fence, dog, neighbor's house etc.