Fable 3, the game in the series we all tried to forget until something worse came along in Fable Heroes, is currently free on the Xbox Marketplace. It's still unclear if this is a bug, since the way you obtain it gratis is a little convoluted, or if this is some portent to today's Microsoft press conference.
Here's how to get the game for free (which we've tested): You must be an Xbox Gold member. Head on over to the game's page and click purchase. Yes, it says that it's $20 (or whatever it is in your regional currency). Now comes the important part. Make sure you are paying with Microsoft Points, not with your credit card. You should see a final confirmation screen identical to the image above listing the game for free.
Enjoy! As much as anybody can enjoy Fable 3.
[Thanks to everyone who sent this in.]