When we first moved into our house, my parents gave us a large glass jar to keep spare change. Over the course of our two and a half years in this house, we've accumulated quite the stash of change. We finally decided to cash it in this weekend, but we made it into a game. We'd each guess how much total money was in the jar, and the person who was the closest would get to choose the restaurant where we would spend (part of) the money for lunch.
Best of all, we have enough to treat ourselves to at least a couple more weekends of lunches, all courtesy of the leftover change from our pockets.