Two years ago there was no escaping “Crazy,” the breakout song from Gnarls Barkley’s debut album, St. Elsewhere. It pumped from bars, supermarkets, sports stadiums, and, seemingly, every radio station on Earth. The Roots, the Raconteurs, the Flaming Lips, and Nelly Furtado even trotted out cover versions. So what’s the encore?

“We can’t do that again, so we might as well not even try,” says Gnarls frontman Cee-Lo Green. Then again, for their sophomore album, The Odd Couple, he and his Gnarls collab­orator, Danger Mouse, didn’t exactly start from scratch. “We sort of employed the old cliché, If it ain’t broke, don’t fix it,” Cee-Lo says.

As such, The Odd Couple combines many of the elements heard on St. Elsewhere, layered with the bigger, outlandish vibe of their elaborate stage show. With its soaring guitar licks (think “Free Bird”), dour organ bits (think “A Whiter Shade of Pale”), and wild-ass beats (think “Hey Ya!”), “Going On” feels like the soundtrack to the funkiest funeral ever. “Who’s Gonna Save My Soul” is a psychedelic gospel freak-out, and “Run” is the sort of frenetic, paranoid soul song that Sly Stone would be howling in 2008 if he weren’t bat-crap nuts.

“I’d love to just get inebriated and write something cool that doesn’t mean anything, but Danger’s music has an uncanny ability to jar introspective lyrics from me,” Cee-Lo says.

The inspiration works both ways. “He writes stuff specifically to impress me,” says Danger Mouse, “so that’s what I do with the music, too. I mean, I did some crazy stuff on this one. We weren’t afraid to be ourselves.”

Still, even Cee-Lo admits that the pressure of following up “Crazy” is impossible to completely tune out. “Gnarls Barkley is a com­modity at this point. You can’t help but be conscious of that,” he says. “But we’re up for the challenge.”