CHICAGO -- Who doesn't like to hit "shuffle" every once in a while? Sure, playlists are cool, but sometimes when your friends come over, it's also fun to spin the dial and see what comes up, maybe impress them with anything from Miles Davis to My Morning Jacket, Britney Spears to Bon Jovi.

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So I decided that my first day of Lollapalooza would be random, a musical buffet that went from hippie pop to British rap, indie rock to electro, with a few stops at everything in between. It began with England's Vaccines, who kicked off the first day of the three-day music orgy on one of the main stages with their ear candy coital anthem "Post Break-Up Sex." Fittingly, I took in their set while chatting with "120 Minutes" host Matt Pinfield, who agreed that the 'Cines sound was a perfect throwback to the good old days of Brit pop and 1980s indie rock.

Wayyyy at the other end of the spectrum (and field) was the hip-shaking boogie of Grace Potter and the Nocturnals, who were serving up a mellowed-down easy vibe with "Goodbye Kiss," a smooth slice of hippie rock that fit the mood of the hazy early afternoon. Potter, as usual, in high heels and a spangly, barely there microdress that ended around where it should have begun, wailed like a new-age Janis Joplin on "2:22" and strapped on a flying V guitar for the band's breakthrough hit "Paris (Ooh La La)," a boogie pop-blues tune that got the audience doing the scarecrow dance.

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Things came down a notch when hometown indie rockers the Smith Westerns took an adjacent stage, playing a set of feathery, soothing tunes like "Fallen in Love," a far cry from the hyped-up, DJ-inspired beats served up a short while later by another Chicago act, former Fall Out Boy bassist Pete Wentz's new band, Black Cards.

Wentz promised a new look with Black Cards and he delivered, as his new band's mash-up of hard house beats, electronic squiggles, reggae riddims and diva toasting-rapping drew several hundred to one of the smaller stages. Wentz, who encouraged fans to check out former FOB bandmate Patrick Stump's set on Saturday, ran between two turntables and the front of the stage as he triggered beats, threw out rolls of toilet paper, crowd surfed and mugged with comely singer Bebe Rexha.

She started out flanked by two scantily clad dancers in werewolf masks who gyrated along to the bass-rattling beats and combo of live drumming and programmed thwaps. "Summer Nights" was a solid warm-weather anthem, with an arm-waving chorus and an assist from a psyched, bespectacled crowd member who was hardly the "bad, bad boy" Rexha was singing about, but who did a mean Pee Wee Herman shuffle.

Beats were also the order of the day for burly British rapper Tinie Tempah, who jacked the huge crowd at his stage with a full-force live band and DJ who provided a thick wall of sound for "Frisky." All the while, Tempah's hype crew worked the crowd by handing out posters and other promotional goodies while wearing giant sandwich boards of the cover of Tempah's debut album, Disc-Overy.

Just down the way at the newly expanded Perry's Tent -- a dance mecca that has grown from a tiny party in a shady grove a few years ago to a massive all-day rave -- the party never stopped. As the afternoon turned to evening, emo rocker-turned DJ Skrillex played a punishing set of thuggish techno party jams to a jam-packed house of daytime ravers who whopped at the sound of every club tune he mashed up for them.

One girl, bleeding profusely from the neck as EMTs attended to her wounds, seemed unwilling to leave, bobbing her head and smiling while perched on a road case as waves of choking heat wafted off the sardine-packed crowd.

As day turned to night, A Perfect Circle could be heard in the distance finishing up their set with a bruising take on "Passive," making way for Canadian indie-tronica duo Crystal Castles. Lolla veterans, the pair did not disappoint the huge crowd that turned out for them, playing a striking set of funky robotic trance rock, with singer Alice Glass bouncing across the stage -- and rolling on top of the crowd like a gothic rag doll.

MTV News is in Chicago for Lollapalooza 2011! Stick with us all weekend as we cover the bands you love and the bands you will love soon.