This is not a game, and it is not really even a toy, either. It is not just a demo, though; it is a finished product of a generator which, like the physics engine that I made which powers it, could be used for many other things. If I was to put a name to the type of thing this is, I would say it's most like a tool or engine it itself.
There are first randomly generated points created using sin(). Ramps are then created from point to point, creating the appearance of a single curved line. The physics engine takes care of the rest.
This was written in AS3 and takes place on a single frame.