First, a complaint. And not even a novel complaint: Can’t people in D.C. just loosen up and dance—-a little?Hercules and Love Affair opened for Gnarls Barkley last night, and they put on a set that could have been epic in another context, but fell a little flat through no fault of the band. They just needed a different audience. Listening to the brainchild of Andy Butler on record, it’s a little hard to imagine the band being a real dancefloor killer—-it’s disco (not death disco or punk disco or Italo disco, but disco disco), but it’s icy and a little bit evil-sounding. Where was the warmth going to come from? Those fears were allayed immediately, though, and the band played banger after banger, starting with “True/False, Fake/Real” and working their way through much of their record, notably blog hit “Blind” and the breathtaking “You Belong.” And no one really noticed.

Granted, the band was opening on this tour, and it’s to be expected that most people in the audience might not know a band that’s only been getting reasonable American distribution of their debut album for a little over a month, but come on. There were ten people on-stage last night, two of them whose sole job was to dance on speakers.There were dueling vocalists Nomi and Kim Ann Foxman going higher and higher (no Antony Hegarty, who sings on the album, but c’est la vie) and sexy synth lines, and a killer horn section to top it off, and people were sitting down. There were at least ten different moments when the club should have exploded, when the band built and built and built something only for it to reach it’s peak and . . . nothing from the audience.

Dance music needs dancing, people.There’s something to be said for the idea that all music is communal, an interplay between creator and listener, band and audience— Jeff Tweedy said as much in Wired a few years ago, and it’s not like there’s an urgent necessity to bust a move during “Ashes of American Flags.” It would seem that it’s more vital for dance music than for anything else, though. Dance music has a purpose beyond just being—-it’s supposed to make you move,and you moving sends energy in to a live set, which sends energy back to you, back and forth in some sort of sweat-drenched hall of mirrors. It doesn’t work if you don’t dance.

Gnarls Barkley’s set worked out better, thankfully, as nobody needs dancing when Cee-Lo Green’s charisma is filling the room. The whole band was tight, and Danger Mouse played his musical Dr. Frankenstein role well, cobbling together something stunning from disparate pieces. It was Green who was the star, though. Declaring himself “Sexual Chocolate” at the end of the set, he earned all accolades, real or imaginary, plowing through material from the band’s two records like he was in a pulpit at a punk show. His vocals on “Transformer” were unreal, as he reminded everyone that soul music means Otis Redding and not Adam Levine. Of course, the band played “Crazy,” and of course, the crowd went appropriately wild. “It’s probably the one you’ve heard the most,” Green said completely unnecessarily before he went in to it.

The real highlight, though, came during the encore. Tucked between gospel dirge “Who’s Gonna Save My Soul?” and show closer “Smiles” “Smiley Faces” was a little song called “Reckoner.” “Reckoning.” By Radiohead. Damn. The delicacy, the paranoia, the power—-everything from the In Rainbows track was still there. It just came with Green’s wail instead of Yorke’s warble. Let’s not take anything away from Radiohead here—-no one’s saying it was better, necessarily—-but one must acknoledge that Green could probably front any band on the planet effectively. Anyway, the club blew up, and while it wasn’t quite consolation for all the times it should have and didn’t earlier in the evening, it was nice to see some acknowledgment for what was a pretty jaw-dropping moment. Maybe there’s hope yet.