Our lead teens Troy (Zac Efron) and Gabriella (Vanessa Anne Hudgens) are from opposite worlds but they meet at a Disneyesque vacation spot during an impromptu karaoke contest and discover, omigosh, they can both sing the daylights out of a tune.

Surprise! After summer is over, Gabriella shows up at Troy’s high school (where he’s best known as a basketballer, not a crooner), and they ultimately decide to tempt fate by going up for the school play. Uh oh! Trouble lurks in the form of Sharpay (Ashley Tisdale) and Ryan (Lucas Grabeel), a conceited brother-sister team who run the drama department with a teenage iron fist. Who’ll win the lead? And what of the big basketball game and academic excellence contest?

You know where it’s going, but High School Musical is surprisingly fun despite its obviousness. It helps that there are plenty of in-jokes (with a name like “Sharpay,” it’s gotta be good), and that the earnest cast members really want to make the film memorable. Some of the songs  are appallingly bad (any of the ones that have something to do with basketball, pretty much), but for the most part it’s hummably decent.