It's a late-summer afternoon on Larchmont Boulevard in Los Angeles' leafy Hancock Park neighborhood, and small clusters of girls gathered in front of Jamba Juice are sweeping the sidewalk with their floor-length skirts. Their T shirts are oversize and piled on in layers. And their sunglasses, with lenses nearly the size of CDs, cover their teenage faces. On the next block, boys with shaggy hair below their ears, wearing rock T shirts from bands that were performing before most of their parents could drive, practice tricks on skateboards.
Eccentric dressing--with such distinctly bohemian touches as shoulder-grazing earrings, long, beaded necklaces and...