[SmooL]

Going to second Carcassonne, and say that one thing I really like about the game is that's almost purely contextless, in that it doesn't require you to hold long-term strategy/ideas/concepts in your head for extended periods of time. If you showed up to the middle of the game, and were told to play the turn for somebody, largely you could. This makes it a great casual game with friends, as a long continuous attention span isn't really required.