When Pong was first released it used paddles, not controllers. Since then it's been controllable by virtually every type of controller known to man, but only recently has it become possible to totally DJ your way through a game of pong.
Serato Scratch Live is software that allows you to use a set of vinyl decks to simulate scratching on digital samples, which is cool enough in itself — especially if you don't have an extensive wax collection. But if you hold the shift and control keys and click on the set-up button, wanna-be DJs can unlock a version of Pong that is totally controllable using vinyl.
It's pretty cool, and as unweildy as it sounds, it looks as though it's actually extremely close to the experience of playing Pong on the original paddles!