Too bad Saint's Row isn't a Game On Demand. Neither is the sequel. November will see Megaman Legends for free, no debating that. October? Probably a horror related game. Dead Rising 2 was already free, so I would think Dead Rising is out. Maybe RE4 or 5? Or Dead Space. December is most likely to be Halo 3. I don't know about Arcade games. I want to play Shadow Complex but not badly. I'd like Banjo-Kazooie or Tooie.
Lakitu is a jerk. He lives in a cloud and throws AIDS at decent, hardworking Americans.
If the years of Steam sales and the ongoing PS+ sale are any indication, there certainly won't be a Call of Duty game. Activision clearly thinks that they're worth even more than what they're charging for them and any digital 'sale' has been pitiful. They're certainly not going to let MS give one away for free.
Fallout 3's a strong possibility, though. Older, has a 'sequel'/companion game also available for purchase on-demand (and plenty of DLC available for both), has already been dirt cheap (at least as low as $5), and Bethesda's not likely to turn them away. I'd say there's a 90% or better chance that we get either Fallout 3 or Oblivion.
Mass Effect and Dragon Age would be good candidates except for the fact that EA would probably play hardball with any attempts to give their games away for free that didn't make them look like really swell guys.
The remain games are gonna be Halo 3, possibly another crap game, crap game, another really good but old game then more crap and more crap and fianlly something good to wrap it all up. Would be great if it was Gta 4 but it is gonna be a game which has a release for xbox during the time period of today and when it finishes.