Just how important are tasty licks and righteous riffs to a young kid's education? If you ask Paul Green the answer is "plenty," and a good number of Philadelphia-area parents agree. There are currently 120 students enrolled at the Paul Green School of Rock Music, an afterschool program for kids aged 9 to 17, and there's only one thing on the curriculum: rock and roll! Zeppelin, Sabbath and, above all, Frank Zappa are on the syllabus. And while Ivy League-educated psychologist Green considers himself a natural teacher, his teaching technique involves pitting students against each other and haranguing them with rants that run from gentle, good-natured ribbing to flat-...