This is the infernal machine that killed poor Maude Flanders on The Simpsons. It also destroyed a hallway light in the Wired office and the left buttock of one of our gadget guys. Like its smaller, paintball-projecting cousin, the Twister 325 Air Cannon generates thrust from compressed carbon dioxide. (Screw those canisters on tight when you reload, kids!) But unlike paintball guns, an air cannon will shoot just about anything you can fit in the barrel. Shrink-wrapped T-shirts are only the beginning! Step 1: Choose your projectile (we like snowballs, cash, or kittens). Step 2: Climb onto your roof. Step 3: Say hello to my little friend!