The man sitting next to me at the Black Penny in the French Quarter is very tall, pencil thin, in a black T-shirt and trousers with a skull-and-cross-bones belt buckle. He leans into his Vieux Carre cocktail with his tattoo sleeves propped on the bar, his pin-striped jacket hanging under it. In New Orleans, he could be anybody—a rocker, a random tourist, just a guy. But in barely 24 hours, he’ll be headlining Jazz Fest with a jazz legend and a pop superstar: Tony Bennett and Lady Gaga.