Music: Group Plink

For 5,000,000 American kids, the return to school means more than seasonal submission to classroom and homework. It means piano lessons, too—usually lonely sessions with a private teacher once a week. But for a fast-growing number of youngsters from 6 to 18, the once dreaded struggle with sharps and flats is now as lively as a trip with the gang to the soda fountain. Well, almost. The burgeoning category of "group" activities—from groupthink to group therapy—now includes the newest wrinkle in piano teaching: group plink. Items:

> In a suburban Cleveland shopping center...