Boards
The Clock of the Long Now is designed to work for 10,000 years.
http://en.wikipedia.org/wiki/The_Clock_of_the_Long_Now
"I want to build a clock that ticks once a year. The century hand advances once every one hundred years, and the cuckoo comes out on the millennium. I want the cuckoo to come out every millennium for the next 10,000 years. If I hurry I should finish the clock in time to see the cuckoo come out for the first time."
– Danny Hillis
It sounds pretty amazing as an idea.