Two years ago, Gnarls Barkley's "Crazy" was the toast of Lollapalooza and covered by multiple performers. This time, Cee-Lo and Danger Mouse returned the favor. Saluting 2008's most adored act, the twosome pulled off a brilliant rendition of Radiohead's "Reckoner." That wasn't the only surprise, of course. The costume-savvy duo came adorned in dark-mustard-colored suitcoats and coordinated bow ties, while their support band modeled maroon sweater vests and white dress shirts. Visually, it evoked Buddy Holly and made for a clever play on private-school instructors and their geeky charges. If only Juilliard could be so soulful. With Danger Mouse manning the keys and reeling off haunted organ refrains, his partner belted out "Run (I'm a Natural Disaster)," "Blind Mary" and "Who's Gonna Save My Soul" as if possessed by a sinister spirit. Nuggets-era garage rock and gospel dirges framed the singer's dementia. After urging the crowd to lose its mind, the Round Mound of Sound closed out the set on a happy note, putting giant grins on faces everywhere with — what else? — "Smiley Faces."