Stickonspy sells die-cut stickers that go around your laptop's webcam to remind yourself -- and others -- that spooks from western governments have made a practice of using spyware that allows them to covertly switch on laptop and mobile phone cameras and microphones to spy on their owners. $3 for one, $10 for 6. We used to sell a variation on these in the old Boing Boing Bazaar. Just remember to trim away enough of the sticker that you can see if the webcam light is lit, which will prevent some of the less-subtle attacks, and also inadvertent embarrassment.
Stickonspy (Thanks, Bradley!)
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.