On Xbox One, Xbox Live Gold members can download The Incredible Adventures of Van Helsing for free during the month of December. Thief will be available as a free download from December 16th to January 15th.
On Xbox 360, starting Tuesday, 01 December, Castlestorm will be free for Xbox Live Gold members through December 15th. Then on December 16th, Xbox Live Gold Members can download Sacred 3 for free through December 31st. And as an extra gift for the holidays, Gold members can get Operation Flashpoint: Dragon Rising for free from December 16-31.