I really like the combination of visual and audio, because they can create amazing effects when used together properly. Music can enhance the effects provided by the video. This is a simple game called ball droppings.

http://balldroppings.com/js/

The way you play the game is set bars on the screens. Balls will come out in a pattern from the same position. When they hit the bars, they will bounce, and they will create hitting sounds. Really simple, right? But after I tried to play it I found how amazing this game is. Since you can put the bars wherever you want, they are infinite possibilities to create a piece of music. There are many balls, and as far as you have enough bars, you can have many balls bounce together, which creates harmony. With different gravity, you can have different pitches.

I will say the way this game attracts me is how simple it is and how amazing it combines kinetics/motions of the balls with music. The bouncing of balls creates music, and it is also the way to visualize music.

It is not a normal way to create music, since it is kind of hard to find the rule of placing the bars to create the harmony you want. But you can find different harmony when place just a few bars. It simplify music and visualize it.