While not exactly about playing games (this is more for the making of games) the launch of Unity 3, the third iteration of the free-to-use game engine, has me excited. Of all the game-making tools out there, Unity is the one I've spent the most time with, and it was actually responsible for the RPS game, RockPaperShotgunity, which we cobbled together last year. Also, I totally made some big spheres move about making booming noises. I am The Creator. People who know stuff are more excited about the unified editor, the post-processing and shader improvements, the occlusion culling, deferred rendering, and other tech stuff. Full What's New list here, although some of that is for the paid-for Pro version, which I think is limited to a month demo, something like that.
Never made a game before? Spong In A Posty! Although that's probably a bit out of date for Unity 3. Maybe it's time to do another one.