Microsoft answered the call of PlayStation Plus recently with their own "free games" program, offering two free games per month for Xbox Live Gold owners. Of course, the program is going to need a lot of work, as PS+ competitively adds more games and newer titles to the mix, but still, it's a thing -- and now it has dates.
Microsoft has announced that on the 1st and 16th of each month, a new game will appear. You can keep checking back with the "Games with Gold" website for updates if you're so inclined, and Assassin's Creed II and Halo 3 are set to headline July.
I mean, it's not PS+ here, but it's a start.