Cuckoo!

The most unique Christmas present I got this year was the cuckoo clock from my father's parents. There's something very cool about mechanical clocks that work by means of weights and gears instead of electronics: when the cuckoo goes off, you can actually watch energy being transferred from the weight to the cuckoo device, as the weight that powers it drops precipitously!

Unfortunately, the clock seems to lose about half an hour every twelve hours. Does the Lazyweb know any techniques for getting mechanical cuckoo clocks to keep better time? I don't mind resetting it once a week or so, but twice a day is a little excessive.