Gillette has a super-geeky Man of Steel tie-in and YouTube takeover going on right now, where they ask an impressive list of celebrities, "How does Superman shave?" Bill Nye, the science guy, offers a theory based in materials science. Super-geek movie director Kevin Smith suggests he uses a piece of the spaceship he came to Earth in (while detailing and dismissing some super other amusing theories, including the one from the comics that he uses his heat-vision reflected in a mirror to burn each hair off). The Big Bang Theory's Mayim Bialik (whom you may know as Blossom, and who also has a real Ph.D in neuroscience) puts forth that Superman has super-Nair. Finally, the MythBusters guys give five or six theories before landing on the Large Hadron Collider. Surprisingly, but not in a bad way, no one said with a Gillette razor. It's a smart idea and a great tie-in. Ad agency Concept One came up with the notion for Gillette. If you want to hash over your own theory, tweet at #HowDoesHeShave. Or just search it to geek out on the crazy pseudo-science theories. Asking comic-book nerds to argue an absurd bit of superhero minutiae on social media? Their evil plan just might work! More spots below.