To characterize 826NYC’s Revenge of the Bookeaters benefit at New York City’s Beacon Theater Sunday night as “understated” would be, well, an understatement.

Of course, any evening hosted by the nearly catatonic (though culturally prescient, completely unflappable and totally hilarious) Demetri Martin is bound to be low-key. Whether riffing on break dancing, goatees or engagement rings, the “Daily Show” correspondent rarely deviated from his steady, somber baritone. As master of ceremonies, Martin’s muted enthusiasm set the bar for the evening’s performances.

In fact, the show — benefiting memoirist David Eggers’ children’s writing center in Brooklyn — had the lo-fi appeal of a Mickey Rooney movie, as if someone said, “Hey kids! Let’s put on a show!” and then grabbed the nearest gaggle of ragged songwriters gathered backstage at McCarren Pool.

To be fair, the casual, mostly acoustic performances by New Pornographer A.C. Newman, Grizzly Bear, Feist, Broken Social Scene, My Morning Jacket’s Jim James and Spoon’s Britt Daniel were entertaining and endearing, if not a hair lackluster.

In fact, the hulking, historic Beacon Theater out-scaled most of the performances. Only James rose to the occasion. A reverb junkie, to be sure, he relished the acoustics, ripping into “Gideon” like a Southern-fried Roger Daltry.

There were other surprises: Grizzly Bear’s oddball cover of Paul Simon’s “Graceland” and A.C. Newman’s version of King Missile’s “Hemophiliac of Love” broke through the static. Still, one was left wondering, is there some kind of hipster code against enthusiasm? Does someone have something against distortion pedals? Snare drums? Scissor kicks?

In the end, the performers’ restraint was superfluous. Longtime 826 supporter Sarah Vowell reminded the audience that the organization’s need for financial support was “a constantly renewable resource,” before introducing chanteuse-of-the-moment Leslie Feist.

At the conclusion of Feist’s story — something written by a group of 826NYC second graders about a family of peanuts with a pickle-shaped limousine — it was abundantly clear: The evening wasn’t about the ironic T-shirt-wearing twentysomethings onstage and in the balcony, it was all about the kids. And the kids are all right, thanks to 826NYC, and the scrappy group of mumblecore-sounding, NPR-loving, Thomas Pynchon-quoting rock stars-in-training.

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