This 1942 ad for a Comptometer mechanical adding machine celebrates the joy of spending hours every day doing what spreadsheets today accomplish in an eyeblink. I love the feature-list: no glare dials, the elimination of non-essential zeroes, and a marvellous "Keystroke Censor."
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.