| NEW YORK — A star-studded medley of musical guests played tribute to Pete Seeger at a benefit concert for the legendary folk singer's 90th birthday. Bruce Springsteen, Dave Matthews, Emmylou Harris, Ani DiFranco and John Mellencamp were among the 40 musicians performing in Madison Square Garden for the Sunday night show, a benefit to raise awareness for Hudson River Sloop Clearwater, an organization Seeger started to preserve and protect the Hudson River. A lone light shone on Seeger as |