It's an odd, 2-player only game made by Jason Rohrer, who is a fairly well renowned indie game maker, which puts one player in control of a person and plays like a point and click game, while the second player IS the point and click game - they create the scenes, and cause reactions to actions.
It's hard to explain in words but the site does a pretty good job with this:
http://www.sleepisdeath.net/slideShow/You can pre-order now for US$9 and it comes out in about 18 hours, when it will become US$14.
Pre-ordering gives you two copies of the game, since it's a two player game although play will be over the internet with many different people (or so I've inferred from the way the custom content system works - you can create your own sprites and anyone who plays in a game you use them will have them to use as well)
Main website:
http://www.sleepisdeath.net/I just pre-ordered it after reading about it on Facepunch but I've already reserved my second copy.
although most of you will probably just go FEH at this game anyway, dont beg for a second copy