Chess Titans is the only one I play regularly. It's great if you feel like playing, but don't have a human victim at the moment. Also, you can select a competence level for your opponent, which would depend how badly you really want to win.
Also I play fantasy football in season, and I'm playing fantasy baseball, which is just starting for this season. Those are computer games to some extent I would say. Those games are great because they keep you totally involved in what's going on with not only your favorite team, but everybody else as well.