What is GBC?
What is a Great Ball Contraption?
A great ball contraption (GBC) is a machine which receives soccer balls or basketballs from one module and passes them to another module, rather like a bucket brigade.
Modules built according to the GBC standard can be assembled into a collaborative display without pre-planning or modification. The GBC standard is minimal, permitting the builder great flexibility in designing the mechanism by which balls are moved from the input to the output.
The otherwise pointless handling of balls, and the myriad ways this is accomplished, gives great ball contraptions the impression of a Rube Goldberg machine.