The term "celebrity inventor" often conjures images of try-hard tech products and goofy marketing stunts (Shaq Soda, anyone?). Not so with director James Cameron, who helped manufacture the cheaper, more versatile 3D filming technology that helped make his own Avatar a reality, and also patented an apparatus that helps camera operators film underwater. In honor of his latest techie feat - directing the world's first live 3D broadcast, a production of "Swan Lake" from Moscow's Mariinsky Theatre - here's a look at eight other surprisingly smart celebrity inventions. Next Francis Ford Coppola: Backscratching t-shirt