Developer:yvan vander sanden
Attr-X is an online multiplayer game about sound. (There is also a single player mode.)
You can walk around in the game world and hear different sounds, or add 'soundballs' which you can alter and move. You can also assign a path to every ball, or pick it up and move it. And all this can be done together with other players.
The first public beta is out and is playable for free. New features will be added over time, like adding filters to sounds and listening to complete soundtracks inside a 'soundDome'.