My wife likes a game called Zelda Wind Waker. My two younger sons enjoy re-makes of earlier video games, like variations on Mario Brothers. My oldest son and his wife will try anything from crazy variations on Tetris, to physical Wii challenges.
I can only guess why they like these activities so much. I'd rather relax with my camera, and then on Flickr and Facebook!
But, when the video gamers get together, I can tell that they've been thinking about their games, even during their busiest times!