Make 671
Make 672
Bill Gurstelle, this one is for you, a triple barrel PIC controlled spud gun –

This project is definitely not small potatoes — three barrels loaded with spuds and charged with propane! Two PIC microcontrollers handle the User Interface, Azimuth and Elevation Aiming and Fire Control functions. Aiming is controlled with a joystick. The Fire Control subsystem verifies a projectile is loaded in the selected barrel before injecting the controlled charge of fuel and that the barrel is armed before firing. It doesn’t verify the operator’s age, sobriety or aim — that’s your responsibility. The chips will fall where they may.

Gadget Freak Case #103: The French Fryin’ Legion’s New Secret Weapon – 6/4/2007 – Design News – Linkvideo & instructions.