Joerg Sprave is YouTube's pre-eminent creator of all things slingshot. On The Slingshot Channel, he shows off his various crazy-genius creations varying from all different levels of lethality. This Sunday Sprave debuted, as he describes, "the world's first drill-powered, fully automatic dart launcher."
Essentially each dart is strapped in a clothespin. Once Sprave powers on the drill, the wheel begins turning, and a specifically designed hand crank fires off the entire round. Sprave mentions that it's not very accurate, and it's not as lethal as some of his other borderline-scary creations, but it's a neat little piece of engineering.
Plus, Sprave's love of creating slingshots is incredibly infectious. I don't know if I ever loved something as much as this guy loves building his awesome slingshot/machine gun creations. [YouTube]