Major Nelson (Microsoft/Xbox representative) have announced the free Games with Gold for Xbox 360 and Xbox One for September 2014.
For the Xbox 360, you can get these games free, to keep permanently, if you have a valid Xbox Gold subscription when you make the 'purchase'.
Monaco: What's Yours is Mine (1/9/14~15/9/14)
Halo: Reach (16/9/14~30/9/14)
For the Xbox One, you can get these games free, and keep as long as you have a valid Xbox Gold subscription.
Crimson Dragon (continuing for a second month)
Super Time Force
So only one new free game for Xbox One; they are keeping Crimson Dragon for another month :| Why the "kind of free" in the title GreenLego?