Guys, this is truly fascinating. You must play it. It's a free MOD for the Source engine. So if you have Steam all you need is the "Source SDK 2007" from the tools section in Steam (which is free) and you can play it. Truly brilliant game design. It's an experimental narrative-driven first person game surrounding the philosophies of choice. I don't even want to say anymore lest I give it away but if you love good writing you should play it. Also, there are multiple...paths you can take. I won't say anymore, but the writing is genius and the voice acting/narrating is very well done. PLAY IT.
The Stanley Parable
There are installation instructions included if you can't figure it out. It should be simple enough, though.