Listen to some relaxing music by adding and removing tracks recorded by SongeLeReveur (http://www.youtube.com/user/SongeLeReveur) for his amazing Nebula One project (http://www.youtube.com/playlist?list=PL4zHtiRylRJK7KWJom8MlkZoqH7SVo0Oe).
Each track features one instrument, and you can add a new track at anytime, any number of times, and make it start from the beginning or from a random time. You can also remove a track at anytime.
There is also a beta module to play a continuous random song...