The first game in Microsoft's Games with Gold promotion is Defense Grid: The Awakening. Hidden Path's 2009 XBLA tower defense game is normally priced at 800 MSP, but will be free for Gold subscribers starting today and until July 15.

Games for Gold, unveiled at E3, sees Microsoft make two Xbox 360 games free each month; one on the 1st of the month, and the other on the 16th. The promotion runs through until the end of the year.

Xbox's Major Nelson clarified through Twitter that the two games already announced for the program, namely Assassin's Creed 2 and Halo 3, aren't this month's pair of offerings.