If you took Peggle or Peglin and stripped out all the gimmicks and flashing lights, then...

well I suppose it would just be upside-down breakout.

But as far as a simple physics game where you're trying to control a chaotic gravity/ball situation, a game that can be quickly intuited by anybody but then when they realize the "gravity" of the task everything becomes much harder, and (again assuming no gimmicks and flashing lights) how quickly I get bored of either? I gotta leave the obvious answer of Peggle and leave it at that.