Starring Gaelan Connell, Aly Michalka, and Vanessa Hudgens. Rated G. Opens Friday, August 14.

The thing I liked most about Bandslam is the notion that a nerdy guy’s knowledge about pop music could make him an instant superstar at his new high school, with two hot chicks filling his dance card. I said I liked that, not that I believed it for a moment.

Newcomer Gaelan Connell plays Will Burton, a curly-topped Lou Reed fan who moves from Ohio to New Jersey just in time to get sucked into “Bandslam” fever. First day in, he’s blown away by a lunchtime rehearsal for the local top combo, expected to yet again win the northeast talent competition. The same day, he captures the attention of extremely happening Charlotte (Disney channel veteran Aly Michalka) and an introspective goth girl (fully clothed Vanessa Hudgens).

Turns out Charlotte and her musical buddies were thrown out of the aforementioned band, led by the usual old frat boy (no, seriously: Friday Night Lights’ Scott Porter turned 30 last month), and now she wants Will to help turn them into a kick-ass new outfit. Suddenly he’s just like Mark Wahlberg in Rock Star, except he’s the manager.

The rock-out scenes are exciting, if overproduced, but in the last, long quarter of this needlessly two-hour-long movie, they are increasingly diluted by sappy family conflicts, including some with Will’s mom, played by a haggard-looking Lisa Kudrow.

As usual for teen comedies these days, the wittiest dialogue (mostly from director and cowriter Todd Graff) comes in throwaway lines. When Will suggests that Charlotte’s wild driving might be less dangerous if she would at least use turn signals, she snaps, “They don’t need to know my business.” I felt the same way about Bandslam’s intrusive back story.