I think there was already a thread on this subject, but I can't remember whether I found it here or elsewhere. If it was here, feel free to post a link, and I'll put it in the OP so people can direct their traffic there.
*ahem*
Post your favourite game that didn't come out in 2012, but that you didn't play for the first time until 2012. Simple?
For me, that's probably X-COM: UFO Defense (the 1993 one). Despite not running particularly well in the DOSBox install, it still runs well enough to not impact the experience too much, and it's an amazingly well-put-together game that everyone ought to play. It's that groundbreaking and amazing and all those other words.[1]
Edit: At time of typing, it is currently five minutes to 2013. I would like to take this moment to wish everybody a happy new year. Let's finally clear out our backlogs.