Most machines have a distinct purpose for which they are designed and they are productive. Sometimes it is fund just to build something for the sake of building something. I am sure that most of you have seen the simple Useless machine, a box which turns itself off. Like this one.
This one takes useless machines to a new level of greatness. The WRO art center in Poland has built a machine which mechanically makes the elevator go between the first and second floor by using a series of pulleys.
Check it out for yourself.