Apparently most of Valve's most popular games (Half-Life 2, Episodes, Portal, Portal 2, Team Fortress 2, etc) are getting updated to work with controllers and TV sets, effectively making your computer into a console.
http://www.steampowered.com/steamworks/thebigpicture.php
Not sure how well it works but still pretty cool.
Big Picture officially live: http://thenextweb.com/insider/2012/12/03/valve-officially-launches-tv-friendly-steam-big-picture-mode/
Apparently it has an interface designed specifically for television.
You can use it on your PC. It looks like an XBox PS3 hybrid...
Well that's the idea, it gives you a gamepad-friendly interface :)