Katamari Damacy is a very cool game, if for no other reason than it is a game in which "scale" changes. The basic idea is that you roll a ball around which picks up objects that aren't too big for the ball and then the ball grows. Usually you are racing a clock to make your ball big enough. I know, I know, it sounds crazy, but it's highly addictive.
But this, this is way cool. A controller for the game which is....a big shiny metal ball:
Back in the mid-80s there was an arcade game where a ball rolled down a winding hill/path through various obstacles and over jumps to the finish. It was controlled by a large ball in a similar manner to the one in the video. Does anyone remember what it was called? It was great fun.
I believe that one was called "Marble Madness."
"Marble Madness" That was it! What ever happened to that game -- is it still around? I loved it.