I recommend a sport: football. Everybody knows what this sport, but everyone doesn't know how it really is. People understand football for 22 people running after a ball, but they don't understand anything. I recommend them to feel what produces this sport, the motivations that provokes, the concentratrion required and the team play. An extraordinary experience.
Someone, three years ago, made me the same recommendation, and now, this sport is the most important things for me.
And girls, don't think that is a sport for men, because the girls as much as we know them.