Haven't played many games this year, and I might've forgotten some, but those that come to mind:
Gray Matter
Portal 2
Skyrim
To be honest, I don't even remember playing anything else... No wait, there was Sam & Max: The Devil's Playhouse, but I guess it's a bit of a stretch to count it in the 2011 list (even though I only found it in retail this year). The three other newish games that I remember playing (there were also the Broken Sword remakes) would all go to the list regardless. I tend to focus only on the best every year
Of course, sometimes I actually get to play them much later than they actually appear...
Not that many interesting games this year though that I haven't played.