Actor Joseph Gordon-Levitt lets it all hang out as Jon Martello, a New Jersey guy who goes to church regularly, eats meals with his parents, takes pride in scoring girls at nightclubs, and compulsively masturbates to Internet porn several times a day. If that performance were all it took, this would be an engrossing character study of a young man on a journey of self-discovery. But JGL, who also wrote and directed, lays on the “Jersey Boy” stereotypes so thickly – with Jon, his buddies, his folks, and his new girlfriend Barbara (Scarlett Johansson) – that it gums up the works. Luckily for all, there’s the figure of Esther (Julianne Moore), a “cougar” earth mother who shows Jon another way. So the impression is of a movie that might have been exceptional, but which is still pretty good. Tony Danza and Glenne Headley costar as Jon’s parents (90 min.).