Well, ive had this on my mind for a few weeks now

http://ghosts.nin.com/main/order_options

nine inch nails have released a 4 cd set, the first of which you can download for free, from their site (see above link)
this is another of the free legal downloads, im getting it right now, purely cos I want to mess about with it and create some nice remixes (they released it under a creative commons – share and muck about with type license)

here is what it says on the nin site

This music arrived unexpectedly as the result of an experiment. The rules were as follows: 10 weeks, no clear agenda, no overthinking, everything driven by impulse. Whatever happens during that time gets released as… something.

The team: Atticus Ross, Alan Moulder and myself with some help from Alessandro Cortini, Adrian Belew and Brian Viglione. Rob Sheridan collaborated with Artist in Residence (A+R) to create the accompanying visual and physical aesthetic.

We began improvising and let the music decide the direction. Eyes were closed, hands played instruments and it began. Within a matter of days it became clear we were on to something, and a lot of material began appearing. What we thought could be a five song EP became much more. I invited some friends over to join in and we all enjoyed the process of collaborating on this.

The end result is a wildly varied body of music that we’re able to present to the world in ways the confines of a major record label would never have allowed – from a 100% DRM-free, high-quality download, to the most luxurious physical package we’ve ever created.

More volumes of Ghosts are likely to appear in the future.

– Trent Reznor, March 2, 2008