Marketing gimmicks aside, pinning down the raw facts on Gnarls Barkley is easy. The group's origins can be traced to an afternoon in 2005 when producer Danger Mouse played a few tracks for soul singer/rapper Cee-Lo. The former Goodie Mob member was impressed with the producer's tracks and suggested that the Athens, Ga. native submit tracks for Cee-Lo's new album. Danger Mouse -- whose production credits include Gorillaz and last year's Danger Doom -- replied matter-of-factly that he doesn't make tracks, he makes albums. The rest, as they say, is history. While it's a clear enough story, the music that Gnarls Barkley makes is more prickly and diverges from anything that Cee-Lo or Danger Mouse have created in their previous endeavors. And though it references nearly everything, it has no real precedent. Is it amoral gospel music, cinematic soul steeped in idiosyncratic underground hip-hop or left-field indie rock with a drum machine and a basketball fixation? Their debut, 2006's St. Elsewhere , is goofy and slippery, falling in the conceptual lineage of other imaginary hip-hop groups such as the aforementioned Gorillaz or Dr. Octagon. It's smooth and soulful, mimicking some the stylistic expeditions taken by Outkast on The Love Below . And finally, it's a mess: disorganized and brilliant; ambitious and nostalgic. Enjoy the music and the mystery.