Marble run
A marble run is a course made for a small ball (or marble) and the aim is for it to travel from start to finish with no flaws.
To make a marble run, you need a small ball. After that, you make a course using anything you can find (see: Rube Goldberg machine).
Marble Run Media
Small part of tallest rolling ball sculpture, Energy Machine, in Hong Kong Science Museum since 1991
People watching a kinetic sculpture by George Rhoads