At one marketing-overrun startup, the suits were calling two hour meetings every afternoon and then wondering why I wasn't getting any work done. So I installed a cuckoo clock in that meeting room. The CEO loved it; he even helped wind it. I knew I'd succeeded when one of the marketing types looked at the clock and said, "I hate that thing." I don't remember if the meetings got any shorter or less frequent, but they…
Love it. A few years ago at a place I was helping out in, one of the devs had built a clock for the conference room that, at the start of a meeting, you punched the number of people in the meeting into. It knew the average company salary (this was a ~15 person software house) and would count up the "money spent" given the number of people in the room and the time on the clock. Very motivating.