Billboard's Best Photos of 2012
Ozzy Osbourne performs at Day 1 of Lollapalooza 2012 in Grant Park, Chicago, August 2012.

See more: The Best of 2012: The Year in Music

The Lollapalooza 2012 lineup was packed with more than 150 rockers, rappers and EDM ravers, who kept crowds rocking in Chicago's Grant Park all weekend long. But as always, there were a few acts who shone above the rest. Here's a look at the five acts (and one unexpected honorable mention) that Lolla fans will remember most from their long, loud weekend.

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Black Sabbath (Friday, 8 p.m.)

Black Sabbath's much publicized 2012 reunion has been plagued with several problems (the health issues of guitarist Tommy Iommi and the departure of original drummer Bill Ward among them), but the masters of metal left the drama behind and gave Friday's Lolla crowd something to scream about during their headlining set. Devil horns raised in the air during the black celebration, as Ozzy Osbourne led the group through their catalog of hard-rocking staples, including "Paranoid," "Iron Man" and "War Pigs."

Florence And the Machine (Sunday, 6:15 p.m.)

Dog days were over for sure when a skipping, quipping, commanding Florence Welch held sway over the packed crowd on the Bud Light mainstage at the northern end of Grant Park. The secret of the set's success? Florence's big sweeping vocals above the band's swelling orchestral majesty (complete with a harp), the titan-haired singer skipping through the photo-pit communing with fans as they sang along, and even the live-debut of "Breath Of Life." Not everyone can make an audience both weep with rapture and want to make love, but Florence at Lollapalooza accomplished it and it felt just a little bit like real-life magic.

Frank Ocean (Saturday, 9:45 p.m.)

The crowd chanted "Frank, Frank, Frank" to welcome Ocean for his rain-delayed set, but everything calmed to a hush when Ocean walked to the mic and kicked off his intimate, 60-minute set with an acoustic cover of Sade's "By Your Side." Ocean and his four-piece live band led the audience through a quiet storm of modern soul tunes that included breakout tracks "Novacane," "Swim Good" and "American Wedding," as well as new cuts from his critically-acclaimed "channel ORANGE" release. But the most rapturous response was saved for the heart-wrenching "Bad Religion," a same-sex love ballad that Ocean said was "important … for some of the things I've said in the past month. It's taken the fear away. I'm grateful for that love." The bandana-wearing singer then closed his eyes and belted out the tune with an almost palpable sincerity that brought the audience to its knees and reminded everyone in earshot why he's R&B's current golden boy.

Childish Gambino (Sunday, 8:45 p.m.)

Coming on the heels of Frank Ocean's equally stellar closing set at the Google Play stage on Saturday, Childish Gambino -- a.k.a. Donald Glover -- had the area packed on Sunday night, closing out Lollapalooza with a massive party. Although the crowd was tightly packed all the way to the street, where Justice's beats could be heard intermixing with Glover's raps, the 8:45 p.m. set felt like the most intimate and engaged of the weekend. Unlike many of the Lolla performers, Glover, who was playing his first ever set at the festival, seemed legitimately excited to be there. And that feel-good energy was infectious, seeping through the crowd until everyone was pumped up. The biggest cheer of the night was when the rapper sampled Adele's "Rolling in the Deep," remixing it and leading the crowd in a massive sing-a-long. Running through an array of high-energy tracks, the audience never missed a beat, singing along to "Bonfire," "One Up," "Unnecessary," and the controversial "You See Me," before Glover ripped his shirt off and bounced across the stage, closing the show in denim cutoffs with the awkward, slightly nerdy, brutally honest sexual anthem "Lights Turned On." After Glover bounded off the stage, sweaty with a grin on his face, the crowd kept chanting for an encore, not giving up until festival producers had taken down half the stage.

Avicii (Saturday, 9:15 p.m.)

When Calvin Harris' early evening set ended at the Perry's stage, a horde of EDM fans turned and made their way down Columbus Dr. to the Bud Light stage where Avicii's set was just kicking off. Shrouded in shadows, the Swedish DJ/producer played his set from inside a giant creepy-but-awesome white head, with lasers shooting out over the crowd. He played "Levels" early in the set, but dropped plenty of other anthems through his 90-minute set, remixing artists from Lenny Kravitz to Robyn as the entire crowd sang and bobbed in unison. Although the EDM star was barely visible during his set, Avicii dubstepped his way through songs like "Fade Into Darkness" and "Seek Bromance," leading the muddy, neon-clad crowd in 90 minutes of fist-pumping.

Honorable Mention: Stormapalooza (Saturday, 4:30 p.m.)

Mother Nature proved to be the real showstopper of Lollapalooza 2012. At around 3:30 p.m., the entirety of Grant Park was evacuated as a massive storm pounded the Windy City. Festival goers and artists ran for cover as the heavy rains came down, but spirits weren't dampened as the party continued in hotels and bars along S. Michigan Ave. until the gates re-opened at 6 p.m. The Chili Peppers, Avicii and other headlining acts went on as planned, but Stormapalooza -- the unannounced act that everyone experienced -- is likely what fans will remember most.

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