Starting Thursday, May 1st, Dust: An Elysian Tail (normally US $14.99) will be free for Xbox Live Gold members through May 15th. Then on May 16th, Xbox Live Gold Members can download Saints Row: The Third (normally US $19.99) for free through May 30th.
The “Games With Gold” program gives Xbox LIVE Gold Members two (that's right 2) free games to keep each month. A new title will be available the 1st and 16th of each month.