CAMBRIDGE -- ''FROGZ" is that rare theatrical event: family-friendly entertainment that is actually friendly to everyone in the family. Neither too preachy for the youngsters nor too pandering for the adults, Imago Theatre's lively, varied program of genuinely inventive theatrics provides nearly two hours of true aesthetic pleasure and truly goofy fun.
And, yes, frogs. To be precise, three remarkably acrobatic performers in amusingly detailed frog masks and stretchy green suits. Their hopping, twitching, and leaping, even more than those whimsical costumes, evoke the very essence of frogginess. And there's a punch line involving a fly that's too good to spoil.
But that's just for openers. Next comes ''Alligators & Lizards," which my 7-year-old companion declared his favorite part. Slithery gators and menacing Gila monsters, wrestling and writhing around the American Repertory Theatre's bare but effective Zero Arrow stage, turn ''just scary enough," in my informant's words, when Jeff Forbes's expert lighting design goes dark to put the focus on their glowing red eyes.
For the adults in the audience, the high point may come at another moment in the dark, called ''Strings." Using black light and mysterious scraps of stretchy material, plus a ghostly white shirt, the nearly invisible, black-clad performers set eerie blue shapes dancing and darting to Katie Griesar's appropriately creepy score. Now resembling blue flames, now undulating waves of light, now fleeting geometric outlines, now some sort of nearly human ectoplasm, the protean blue whatchamacallits have a spooky beauty that's oddly and deeply satisfying to behold.
That's the kind of sensation that the creators of ''FROGZ," Carol Triffle and Jerry Mouawad, are clearly aiming to produce in their Portland, Ore., theater, whose work has toured internationally (''FROGZ" has visited Broadway twice). And they've wonderfully trained the performers here: Rex Jantze, Jonathan Godsey, Kyle Delamarter, Danielle Vermette, and Leah James Abel. Schooled by Jacques Lecoq, the late French master of dramatic movement, Triffle and Mouawad create theater that is deeply rooted in the physical experience of its performers, and that in turn connects deeply with the physical sensations of the audience.
Sometimes that results in such radical productions as their adaptations of works by Richard Foreman and Jean-Paul Sartre (ART audiences will see Imago's ''No Exit" next season). But sometimes, as in ''FROGZ," it leads to work that's accessible to a wider audience but, in its way, no less boundary-stretching. It's unfortunately rare in our culture to come across work that is both intellectually challenging and truly entertaining; Imago reminds us that the combination is not only possible but essential -- and does it in a way that lets even a child get the idea, laughing all the way.
Take ''Larvabatic," in which a lone performer, clad in a segmented brown costume that turns his feet into forelegs and his head and torso into a ''tail," plays around with our perceptions in a way that's both thrilling and hysterical. When he does a ''handstand," muscles trembling in a pretense of intensely focused effort, he's really just standing on his feet with no trouble at all, but we gasp at the illusion of a difficult balancing act, even as we're laughing at seeing through the illusion. Now, that's entertainment.
It's true that not every moment delights. To my taste, a routine involving combative accordions went on too long, and I'm still puzzling over some polka-dotted sloths. But then I think of the wacky penguins, playing musical chairs with deeply comic seriousness of purpose, or the magical ''Paper Bag," whose mysterious coming to life ultimately explains itself in a way that makes you realize you see such magic every day, and reminds you to pay attention when you do. I can't think of a better way to introduce my son to the rewards of art -- and he didn't even notice that he was getting an education, because he was having such a good time.