If we're talking about games played in 2012? It's a toss up between Saint's Row: The Third and Journey, if we're sticking to games released in 2012, then Journey wins hands down.
Umm... since I haven't played any major 2012 games other than phone games I'm going to have to go with Dungeon Village by Kairosoft. Those people know how to make obscenely fun micromanagement games and Dungeon Village is one of the best since Game Dev Story.
I'm too wrapped up in hot 2008 releases like Burnout Paradise along with the classic 1998 blockbuster WCW/NWO Revenge for the N64.
I mean just listen to this music, it's so good you can hear the crowd cheering about how awesome it is in the background.
I've actually been keeping a list, so I'll just stick that in here. My favorite of these is easily Journey. I just finished playing it, and man, it was beautiful in every sense of the word.
Games I Played in 2012
All of the games that came out in 2012 that I purchased and played... that I can remember to put on this list