I participated in a collaborative release that has just been released. It's called "Collusion", and it's available for free download at this link from Intelligent Machinery Dot Net.
In this collaboration, one dozen artists submitted independent noise and dark ambient tracks, which were then overlaid upon one another in sequential form, with each artist's piece being worked in and then fading out of each section of the track. I'm part of minutes 31 to 38, but the process is so seamless that one would never guess it is three different artists' work overlain upon one another's tracks.
I'm very pleased to participate in this Creative Commons release, as I enjoy the niche of experimentation in dark ambient--in looking at completely new ways of "seeing" music, and of "feeling" its power.