Matt sez, "Here's a link for the Herobrine costume I made for my son. After a bunch of requests, I put up the PDF files and instructions to make your own. It was a huge hit with the kids at his school. Even bigger than when we went as Finn and the Ice King last year!"
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.