Alright, I went back a few pages in the XBLA thread and that thread is a monster to find things. I think there's enough to the Summer of Arcade to warrant a separate thread.
http://www.xbox.com/en-US/community/promotions/summer-of-arcade
Buy Three and Get a Bonus
Purchase any three of the five Summer of Arcade hits and you'll get 400 Microsoft Points as our way of saying thank you. The points will be automatically added to your account at the conclusion of the promotion.
* Purchase any 3 Summer of Arcade games: Tony Hawks’ Pro Skater HD, Deadlight, Wreckateer, Hybrid, and Dust: An Elysian Tale before August 21, 2012, 11:59pm EST, and 400 promotional Microsoft Point! Limit one (1) gift per person. To qualify for your gift, you must purchase any three of the five featured games from Xbox LIVE Arcade using your Xbox LIVE account, by August 21, 2012 11:59 EST.
Tony Hawk's Pro Skater HD
Available July 18
1200 MS Points
Wreckateer
Available July 25th
800 MS Points
Deadlight
Available August 1st
1200 MS Points
Hybrid
Available August 8
1200 MS Points
Dust: An Elysian Tail
Available August 15
1200 MS Points
http://www.xbox.com/en-US/community/promotions/summer-of-arcade
Buy Three and Get a Bonus
Purchase any three of the five Summer of Arcade hits and you'll get 400 Microsoft Points as our way of saying thank you. The points will be automatically added to your account at the conclusion of the promotion.
* Purchase any 3 Summer of Arcade games: Tony Hawks’ Pro Skater HD, Deadlight, Wreckateer, Hybrid, and Dust: An Elysian Tale before August 21, 2012, 11:59pm EST, and 400 promotional Microsoft Point! Limit one (1) gift per person. To qualify for your gift, you must purchase any three of the five featured games from Xbox LIVE Arcade using your Xbox LIVE account, by August 21, 2012 11:59 EST.
Tony Hawk's Pro Skater HD
Available July 18
1200 MS Points
Wreckateer
Available July 25th
800 MS Points
Deadlight
Available August 1st
1200 MS Points
Hybrid
Available August 8
1200 MS Points
Dust: An Elysian Tail
Available August 15
1200 MS Points