oh, one more thing… marathon 2: Durandal [not sure how long it's been out, but i only noticed it recently]
I believe Durandal for iPad was released on December 15, 2011. The current version 2.3 appeared on January 7, together with the 2.3 update for Marathon 1.
And while we're on the Marathon topic, December also saw a major update for the Mac versions. Details HERE.
