Giants prove a nice fit for smaller fry

“Welcome to the world of rock music. All rock concerts are exactly like this.”

Vocalist-guitarist John Flansburgh, the outgoing half of the off-the-wall, strangely wholesome alternative rock duo They Might Be Giants, aimed his deadpan comment at the band’s newest audience: small and middle-sized kids who, along with moms and dads, pretty much packed the concert presented by UCLA Live at Royce Hall on Saturday afternoon

Flansburgh’s remark followed a burst of cannon-shot confetti that rained down over the front rows. It was that kind of show: rowdy, playful and participatory, with children crowding the “dance area” in front of the stage and screaming like crazy. A majority of their elders screamed too, and clapped, jumped in the air and did a choreographed “wave” as enthusiastically as their offspring.

A lot of TMBG’s smart and witty work is inherently kid-friendly, and the band mixed in several songs familiar to adult fans -- “Particle Man,” “Istanbul (Not Constantinople),” “Clap Your Hands” -- with selections from its first release aimed at children, 2002’s multimedia CD, “No!,” and from “Bed Bed Bed,” its 2003 book-and-CD set.

The other half of They Might Be Giants, the laconic John Linnell, played his trademark accordion and keyboards; Flansburgh, who wears his nerdy, bespectacled persona with the utmost sincerity, did most of the talking and maintained a deft balance between focusing on children in the audience and acknowledging adult fans.

Musically, there was no sense of holding back because this was a kids matinee, either (the band’s adult concert took place that evening).