Here's an awesome weekend project that could leave you with a fearsome "Ping Pong Ball Mauler" capable of firing hundreds of balls a minute at your unsuspecting neighbors.
Christian Reed built it out of a poly drum and a homemade pneumatic device. He turned a standard shop vacuum into a high volume, low pressure system that allows his contraption to continually fire a constant stream of ping pong balls at a rate of hundreds of balls a minute. Best of all, all of the parts he used can be bought at any well-stocked home improvement store!
He documented the entire process at Instructables, including detailed instructions on how you can build your own. See the Mauler in action below, and head on over to his tutorial to give it a try yourself!