[sanddrag]

That would be a lot of fun and everyone would do it however even with the waivers you'd get sued for way more than you would ever make. Also your school would earn a very bad reputation from local media.

Here's my proposal. Take an old or cheap bench grinder and mount it on a table. Get some cheap pieces of steel (lets say steel pipe). Have the table with grinder down in the gathering area at lunch time at your school. Charge $2 for 30 secs of sending the steel pipe into the grinder making a showering array of sparks. The kids would love it and the sparks would draw a lot of attention.

This idea could actually be made safe by having a plexiglass or similar clear box over the grinder with a hole to put the pipe through.

Flawless.