MUSIC: A group of West Marin School eighth graders will perfom for the last time together during the Western Weekend parade on Sunday.   David Briggs

There are 20 minutes left before the bell rings and Kids Who Rock, a rock band comprised of West Marin School eighth graders, is running through its West Weekend set for the final time before their flatbed truck stage parades down Main Street. 

Dave Whitney, the school’s music teacher, directs the ensemble of four singers . . .