
Creator: cipher prime studios
This is a game I found today. The idea of the game is to change the direction/color of the light in the direction of the (?) objects, so they make sound.
http://www.playauditorium.com/
The handling of the game is easy though it takes a few seconds to figure it out.

Creator: reflexive.com
You need to catch as many signs as possible. The yellow ones give you a multiplicator of your points and the red ones take the multiplicators away and the purple ones work as a huge vacuum cleaner :) The blue tiles are points. Basically you don't need to play at all the music in the background is exquisite! :)
http://www.reflexive.com/index.php?PAGE=WebGamePlay&WGID=94
Update:
Music catch continues with:
Music Catch 2
Creator: reflexive.com
The principe is the same, new music pieces, and some small visual updates
http://www.reflexive.com/index.php?PAGE=WebGamePlay&WGID=182

Creator: k2xl.com
Just click a spot and watch the points expand. If you touched enough points you get to the next level. Very pleasing continuous music. This is the oldest game of these three, before the fancy animations could be used. In general this can be seen as an evolution of this kind of games :)
http://www.k2xl.com/games/boomshine/