I like to relax with LEGO Lord of the Rings.
Running around, solving simple puzzles, and collecting things. It's unchallenging, but not mind-numbingly so. Add the fact that it features musical score and voice acting taken from the Jackson films (which I love), it's just a great opportunity to spend time exploring a child's toy box version of Tolkien's world.
I imagine the same could be true for a lot of older gamers if they found a LEGO game with a setting that they really loved.