They’ll deny it, but most college students who write plays harbor some secret fantastic hope that their new opus will be hailed as the arrival of a fresh new voice and open on Broadway to triumphant acclaim. It obviously never happens, except when it does: 28-year-old Lin-Manuel Miranda, originally from Washington Heights, conceived the musical In the Heights as a sophomore at Wesleyan. After graduating, the show, a hip hop and salsa-inflected homage to his......