400 years is an adorable and clever browser-game where you play a kind of ambulatory stone pellet on a quest, wherein you overcome obstacles by holding down the spacebar to make the seasons fly past and the years go by, while a tree grows tall enough to climb, or winter arrives and freezes a pond so you can cross it. But don't hold the spacebar too much -- you've only got 400 years to get through the game!
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.