If you're the sort of person who resents when your roommates and friends repeatedly steal your favorite mug, boy do we have the solution for you. Meet the Lock Cup, the ingenious invention from industrial designer Efrat Gommeh. Simply insert the key when you want to fill up on your favorite beverage, and remove it when you want to make sure no one else can drink from it. Sure, the invention seems a little "dog in the manger-ish", but on the other hand, it looks like a hole lot of fun. Click here to view more.