I'd like to be able to "invent" sports. They could work like religions. A civ invents a sport, then spreads it to other civs, increasing good relations. Unlike religions, the more sports there are, the better the relations. What I mean is, there aren't negative penalties for having a particular sport more popular in your empire than another civs. You could have Golf as the most popular sport in your empire, with Tennis second most popular. Another civ could have Tennis as their most popular sport with Golf second. If these were religions, the civs would be upset. But because they play the same 2 sports, they would get really good relations with each other. I hope this makes sense.