http://msdn.microsoft.com/en-us/evalcenter/jj554510.aspx It's the final version of Win 8 Enterprise (whoosh!). it'll expire after 90 days, and will not be able to upgrade afterwards.
For anyone interested in giving it a look-see. While I have not tried it for myself, I've read very little good about it, so I doubt that I'll be getting it. MS seems to be keeping the tradition of every second OS release being lousy: 8, Fista, ME, '95, etc.
Plus new Nvidia and AMD GPU drivers for it have been released. Lamely, Directx 11.1 will apparently only be for Windows 8. Pretty stupid, as 7 is fully capable of using it.