Scot Nery sez, "Here's a quick fun video showing how to do the coin knuckle roll. Make your local magician respect and envy you."
HOWTO roll a coin across your knuckles
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.