The Stanley Parable is now available on Mac OSX 10.8 and higher. Writer Davey Wreden tells Joystiq that support for earlier versions of Mac OSX is planned through an upcoming patch.
The game is currently 40% off, down to $9, in the Steam Holiday Sale right now. A free demo for The Stanley Parable, which you can grab through the Steam app page, has been available since October 10.
In The Stanley Parable, players guide the titular Stanley – an employee at a nondescript office building who suddenly finds all of his coworkers have vanished. We loved The Stanley Parable, as evidenced by our review lauding the game's elaborate and self-defining experiment on players.