Obviously play with your cat. But if you play with your cat ten minutes before meals you simulate the natural hunting instinct. Curbs misdirected aggression and also I think makes them enjoy their food more. Just my two cents.. that Jackson Galaxy agrees with.
Me and my girlfriend have been getting into tennis its so fun. Your body moves in a really great way when you play and makes you feel glad. I still suck but am starting to be able to get a volley going from the backline. It is a good feeling to hit that ball right and run around. Almost as good as soccer.