I've always thought that sports games sell next-gen systems. It gives an easy bar to measure the quality of the graphics against. It's something relatable to most people and everyone is always pushing towards the most "realistic" looking graphics possible. Sports games are inherently co-op, usually offering offline co-op for gamers to team up against the computer. We typically only list sports games in our database that have explicit co-op modes; like online franchises, leagues or second screen stuff designed to be played against the computer.