In this trade-show-floor video, a Japanese inventor shows off his ~$6,000 "suction mat," uses a sensor-triggered grid of vacuum nozzles to suck the grime off your shoes before you come through the door. It reminds me of the air-showers in the airlocks leading into chip-fab cleanrooms, and appeals to my inner compulsive neat-freak. Combine this with a couple autonomous vacuum bots to follow you around and suck up any skin-cells you shed while you're hanging around, and it'll be like you were never there.
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.