The game launched in beta in February 2013, and it allows players to create their own character and use intrigue and power plays to become an important player allied to one of the Great Houses.
It's a Facebook game, developed by Disruptor Beam. I know it's heresy to praise a social game, but 'Game of Thrones: Ascent' is one of the best 'Game of Thrones' games out there. And it updates every week along with the show.
Game of Thrones: Ascent, on Facebook, is surprisingly good.