LA's Secret Headquarters (best comic shop in town!) has a limited supply of t-shirts based on Brian Wood's wonderful DMZ comics. They bear a sterling Wood illustration on the outside, but can be reversed to reveal the word "PRESS" screened in white on the inside, for those moments when you want to be identified as a non-combatant. Link
(Photo of me modelling tee by Greg Ehler)
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.