George Pimentel, WireImage They started showing up as early as Friday: Deadmau5 heads, or Mau5heads, the iconic beach-ball-sized helmet worn by the Toronto house DJ/producer also known as Joel Zimmerman. Why anyone would want to lug the massive, heavy headgear around a music festival, especially on Sunday when it poured at Lollapalooza twice, ...

Tim Mosenfelder, Getty Images "We're the Arctic Monkeys from High Green, Sheffield, Australia," frontman Alex Turner announced from the Lollapalooza main stage Sunday evening. No, the Arctic Monkeys are not from Australia, and on Sunday the four-piece brought their native, bleak British weather to Lollapalooza 2011. A torrential downpour ...

Rob Loud, Getty Images Lollapalooza is big. It's a mile-long walk between the festival's two main stages with 90,000 music lovers filling in the big gap. And on Saturday night, America's biggest-selling artist of the last decade drew what could go down as Lollapalooza's biggest crowd to date to the fest's biggest stage, and still made it feel ...

John Shearer, Getty Images for the Recording Academy When Coldplay closed out their headlining 19-song Lollapalooza set with fireworks, things turned a little too real for those up front. As rapid-fire explosions went off above the stage to the beat of their new track 'Every Teardrop Is a Waterfall,' a waterfall of tiny black gunpowder ...

Timothy Hiatt, Getty Images Grace Potter wears two pairs of underwear. "You got to have your s--- straight underneath," the gorgeous singer, known just as much for her soulful, wall-of-sound vocals as she is for rocking out in her trademark gravity-defying, sparkly mini-dresses, tells Spinner before her Friday set at Lollapalooza 2011. ...

Douglas Mason, Getty Images Last month, many drove hundreds of miles and waited hours just to see Buffalo Springfield, fresh off a 40-plus-year hiatus, play Bonnaroo. The wait was worth it as Buffalo Springfield -- surviving founding members Richie Furay, Stephen Stills, Neil Young plus bassist Rick Rosas and drummer Joe Vitale -- played ...

Rolling Stone Standing in one corner are Canadian alt-rockers the Sheepdogs, and in the other, sassy L.A.-based singer-songwriter Leila Broussard. Both are squaring off in the first-ever Rolling Stone Cover Contest, where one act will be left gracing the front of the rock magazine's Aug. 18 issue. Voting for the last round of the competition ...