Windows 8 showed up on these great internets for all to download -- illegitimately. An early version (6.1.7850) has been making the rounds at manufacturers and it's finally escaped the confines of beta labs. We haven't braved the torrent sites ourselves to download this, and we certainly wouldn't recommend that you do, but the screenshots we've seen definitely peg this particular revision as a slight evolution of Windows 7, seemingly not including all the revolutionary tweaks to come. It's still early days, remember. Plenty of time left for the magic to happen.
[Thanks to everyone who sent this in]