In one of the most iconic moments in American movie history, underdog prizefighter Rocky Balboa runs up the stairs of Philadelphia’s Art Museum as “Gonna Fly Now” triumphantly blares in the background. Obviously, tourists to the city regularly visit the staircase to reenact the epic scene and relive the magic of the Rocky franchise. This week, a group of friends got the surprise of a lifetime when Rocky himself, Sylvester Stallone, happened to spot them. One of the lucky fans explained to Philadelphia news station 6ABC, “He said to us, ‘Man, you guys are fast. You’re making me look bad!’” Stallone, who was in town to film yet another addition to the series, even posed for a selfie with the Rocky fans. Even when he’s not in character, Stallone still manages to inspire greatness …