The following plot synopsis is for those who have no idea what I'm talking about (the rest of you can drum your fingers in boredom and listen to Green Day sing ''Extraordinary Girl" again). It's the beginning of the summer, and four 16-year-old best friends in suburban Bethesda, Md., are parting company for the first time in their lives.
Beautiful, brittle Lena (Alexis Bledel of TV's ''Gilmore Girls") is going to stay with her grandparents on the Greek isle of Santorini. Bridget (newcomer Blake Lively) is a blond queen-bee jock headed for soccer camp in Mexico. Carmen (America Ferrera of ''Real Women Have Curves") is a budding writer insecure in body and mind; she's finally going to spend some quality time with her estranged father, Al (Bradley Whitford) in Charleston, S.C. Tibby (Amber Tamblyn of ''Joan of Arcadia"), the resident cynical punkette and the movie's closest approximation to an authentic teen rebel, is stuck working at the local chain megastore. She's also shooting a documentary about her summer that might as well be called ''Why I Hate Everything."
Oh, yes, the pants. Carmen has bought a pair of weathered thrift-shop blue jeans that mysteriously fit all four of the friends, and more discreetly radical than this borrowed bit of Latin American magical realism is the notion that girls (and women) come in all shapes and sizes, none of which are the Olsen twins.
So the pants, mailed from one girl to another every two weeks, become the link that connects them. There are additional rules -- no laundering, no double-cuffing, no letting anybody but you take them off. They could've added, ''No admitting the pants are a metaphor for life's unexpected growth experiences," but that would give the game away.