The iPlayer is a hardware video-decoder for your Nintendo DS. It plugs into your cartridge slot, and uses its on-board processor to send video in a variety of formats (avi, mov, RealPlayer, wmv, DivX, Flash, 3GP, asf, mpeg) to the screen and speakers. You load the video through a MicroSD card. Haven't tried it, got no idea if it's any good, but the premise is delightful.
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.