More than 650 people showed up to watch Keegan-Michael Key, of “Key & Peele,” pick up the player of the year award from the Harvard University improv group the Immediate Gratification Players on Friday night. “I’d say about 100 got turned away,” said group “czar” Aaron Hendricks, a Harvard junior. “The cops wouldn’t let anyone else in.” The night featured plenty of improv by Key, who did monologues and performed with students. “It’s like swimming with Michael Phelps. He’s one of the best,” Hendricks said. “He got a standing ovation immediately when he walked out.” The last person to win the group’s player of the year award was “Seinfeld” star Jason Alexander.