What is this?
  Well.. I had this idea.. get several music-makers together and make a track. Each will make their part (one to bass, one to melody, and so-on) without listening to the others' part. A BPM and maybe a theme or scale is decided beforehand, and when everyone is finished, it is mixed by one of the participants or preferrably a person that only does mix.

The general idea for the tracks is that they're supposed to be as spontaneous as possible, which means it would be preferrable for them to be done within an hour or two (including the process of getting artists), so don't sign up unless you have the time. It seems like the projects most likely will be started as threads on different forums where music makers and artists hang out.