If the punks, goths and weirdos of the world voted on their favorite string ensemble, San Francisco's Kronos Quartet would be a likely contender. What other string quartet has covered Television's "Marquee Moon"; duetted with Mexican alt rockers Cafe Tacvba; and devoted nearly an entire album to Sigur Ros? The group has highlighted African composers in one decade (on 1993's charting Pieces of Africa) and then gone on to pay tribute to Bollywood (on 2005's You've Stolen My Heart) the next. Founded in 1973 by violinist David Harrington, Kronos were initially inspired by George Crumb's eerie and experimental look at the Vietnam War, Black Angels (later the title of an excellent 1990 Kronos album). The players (Harrington, John Sherba, Hank Dutt and Joan Jeanrenaud, later replaced by Jeffrey Zeigler) have mentored composers and players and developed long-running relationships with renowned minimalists like Philip Glass, Terry Riley, Henryk Gorecki and many others. But the members never let any dogma cloud their explorations, and the result is a growing discography of more than 40 albums that are breathtaking in their scope and virtuosity.