User: Why is Football a popular spectator sport?
Assistant: Football is an exciting game that is fun for people of all ages to enjoy.  Many fans of the game follow a team that is associated with a school or town/city.  Football is a fast moving game where players run, tackle, pass and kick a ball on a 100yd long grass or turf (fake grass) field.  Referees make sure players follow the rules and if not, they stop the game and penalize the team which committed a foul/penalty.  College football is very popular as well as professional football.  The NFL (National Football League) is the league with the best professional players.