Major Nelson has updated this blog with a list of what we can expect in the Summer of Arcade event which starts in just a few weeks time. Dated and priced are:-
July 22 – Teenage Mutant Ninja Turtles: Turtles in Time Re-shelled 1200 
July 29 – Marvel vs. Capcom 2 1200
August 5 – ‘Splosion Man 800 
August 12 – Trials HD 1200
August 19 - Shadow Complex 1200
Hope you’ve stocked up on the Points, because you’re certainly going to need them if that lot tickles your fancy.
TMNT looks too expensive, but all other titles look like they have a good price for what they offer, especially considering Shadow Complex was supposed to be $20.
I was surprised at the price of Shadow Complex (in a good way though), particularly since they were warning it would be expensive as recent as last month.
I’m really looking forward to that one and will be all over it on day one.
Also they’ve just tweeked the release date slightly so that TMNT isn’t the first any more:-
http://www.console-arcade.com/2009/07/10/microsoft-revises-its-summer-of-arcade-schedule/