Don’t bother telling Joe Rockenbach your curling jokes. He’s heard them all. As president of his local curling club, Rockenbach has listened to people tell him that curling is not a real sport. Or about how curlers must be skilled house cleaners because their sport involves sweeping. Those comments used to irk Rockenbach, a 37-year-old Philadelphia native, but he’s seen the game humble enough people that now the slights slide right off. “Almost anybody who comes into it with the attitude of, ‘This is nothing, I got this,’ when they get off the ice, [they say], ‘this was way different...