Remember how we told you Google Games was coming, and how it's going to pack multiplayer functionality, leaderboards, achievements, and stuff like that? That's happening. There are going to be cloud game saves too.
Fresh out of Google HQ, we've managed to score a copy of the new Google Play Services v3.1.36, which is very slowly rolling out to devices right now. For comparison, the current Play Services that most people have is v3.0.27. 3.1 is a massive update - the strings file, for instance, has more than doubled from 300 to 700 entries. This is how Google is pushing out all the shared files for Google Play Games.