OH! I also read a bit of a biography or novel with a character who I find inspirational or motivating. Nothing says "get back to work you lazy bum" more than a super-high-achiever from a terrible troubled background overcoming social taboo and prejudices to change the world!
Play stupid games on Facebook! Either that or do housework, when I can be bothered, which isn't that often! But I feel the same, I need a way to avoid looking at the screen when I'm taking a break.