Tonight at 7:30 at Severance Hall, you can catch a screening of the classic flick An American in Paris, while the Cleveland Orchestra performs the soundtrack. The musical stars Gene Kelly as an American ex-GI who falls for Parisian Leslie Caron. Better still, the movie features some of George and Ira Gershwin's most unforgettable songs. An hour before the show, Bill Rudman, artistic director of the Musical Theater Project, gives the pre-concert lecture. The program repeats tomorrow and Saturday. Check the orchestra website for ticket prices and more info. (Niesel)