Hm, I've been trying to get rid of one particular habit (drinking while sitting at my computer) for a long time. Recently I've considered the possibility of giving myself a reward every time I go to the kitchen to get a beer and come back with something else instead. The problem was that I couldn't think of a suitable reward (there's not much that I like). I hadn't thought of just making something up, like pieces of paper. Thanks for the inspiration!