The fairly recent loyalty program, Xbox Games with Gold, has been confirmed by Microsoft as a permanent feature that will continue on past the Xbox One's launch. Before this confirmation, it was discussed by Microsoft that the promotion would only stay till the end of the year, but it looks as if somebody has managed to convince the big M to keep us a little bit happier with our monthly Xbox Gold subscriptions.
The Xbox Games with Gold loyalty promotion offers two free games each month to everybody who has an Xbox Live Gold account. It started out with little mention from Microsoft when Fable III mysteriously appeared on the Xbox marketplace for free, but it was later revealed that the game was part of the ongoing Games with Gold loyalty service.
Since then, Xbox Live Gold members have been treated with a bunch of fairly outdated games over the last few months, including games like Halo 3, Assassins' Creed II, Dead Rising 2, Crackdown and Might and Magic: Clash of Heroes.
Currently Halo 3 is available till October 31st as a free title, and after this date Microsoft will introduce another game that will be available on the Xbox Games Store for half a month.
Once a game has been up for half a month it will then be available for purchase again through the Xbox Games Store.
However, Xbox Live Gold players can "buy" the free title and then play or download it whenever they feel necessary, even after the promotion runs out or their account reverts to a free account.