This is an experimental "game" created by some guy in a few days. It's called SCP-087. There is no gameplay, it it an atmospheric horror staircase experience. All you do is walk down a dark set of stairs, getting more nervous as the sounds change.
http://www.mediafire.com/?5cadimaeo004aee - windows download
http://www.mediafire.com/?5sbi5a0e8mwhbto - mac download
Haven't tried it yet. but should be.. atmospheric. Maybe?