Flights of fancy on the satire runway

Flight of the Conchords operates on another dimension. That was clear enough Friday from the band’s performance at the Orpheum Theatre, where the duo opened with the electro sci-fi song “Robots” and its cautionary tale of the fall of mankind and the rise of the befuddled machines: “No more war, no more racism . . . no more yogurt.”

The two singer-songwriters began the song in silhouette, possibly to disguise the embarrassing absence of proper robot costumes. Jemaine Clement (the one in glasses) moaned melodically and mechanically as Bret McKenzie (the other one) sang a binary vocal solo: “Zero, zero, zero, zero, zero, one / zero, zero, zero, zero, zero one-one . . . “

This was stupid and playful, and the reaction was big laughs and wild applause. It was the first of two sold-out nights at the venue for Flight of the Conchords, a lo-fi musical comedy duo from New Zealand, whose HBO comedy series of the same name has spread the band’s understated insanity and biting, meandering tunes to a new American audience since its 2007 debut.

Their specialty is musical parody and absurdity to the point of surrealism. It’s an inspired tradition: In the ‘80s, “This Is Spinal Tap” portrayed a band of clueless metal gods in decline; in the ‘90s, it was Tenacious D -- a pair of clueless fans and wannabe metal gods going nowhere. Now on HBO, Flight of the Conchords is a kind of clueless indie folk-rock duo looking for love and fame with no help at all from their equally inept manager.

For the real-life Flight of the Conchords, songs often still work best in the context of larger on-screen comedy, but the band was also a hilarious live act in their jeans and rolled sleeves, playing acoustic guitars through their deadpan streams of consciousness. Songs were tuneful and pleasant and ridiculous and inane and mostly drawn from the band’s new album, “Flight of the Conchords” on Sub Pop. Even McKenzie nearly cracked up a couple of times.

During “The Most Beautiful Girl (In the Room),” the duo plucked a lilting tune and purred, wept and sang in hushed tones: “You’re so beautiful, you could be a waitress . . . you could be a part-time model.” Another song told of a pair of starving sailors lost at sea, slowly eating each other, piece by piece -- without permission. And there was a new breakup ballad, sung by Clement: “Jen said she would never see me again / When she saw me again, she said it then.”

There were loving parodies of Barry White (the heavy-breathing “Business Time”) and David Bowie (“Bowie”). “Foux Du Fa Fa” had a samba beat as the singers moaned romantically through some random words in French: “Baguette, fromage . . . soupe du jour, Jacques Cousteau . . . voila, uh-huh-huh.” It’s an old joke, but stupid, clever fun is forever fresh.

They are aspiring rock stars, after all. They know their responsibilities. So they also did a song about “issues,” even if the specific issues were not so important. “War, poverty, whale saving,” said Clement. “Anything Bono is into, really.”