This is a small dupe of an older post, but I thought it was justified posting this as a reminder.
Today only FEZ (was 800 MSP now 400 MSP) and Mark of the Ninja (was 1200 MSP now 600 MSP) are half price on the Xbox Marketplace.
These two games are two of the highest rated XBLA games of 2012.
Fez metacritic rating: 89
Mark of the Ninja metacritic rating: 90
Other games are on sale, including Trine 2, check the Major Nelson link.
Mark of the Ninja is 600 points.