Forget “Tristram Shandy”; how do you make a movie out of a book about a mute monkey whose typical adventures consist of riding a bike?

The new film “Curious George” carries all the risks of adapting books intended for very young children to the big screen. Brief plots, (literally) two-dimensional characters, and happy endings can turn into Hollywood schlock all too easily. The carnie nightmares that were the “Dr. Seuss” movies, for instance, are enough to put people off adaptation (or food) altogether.

Yet kiddie lit is well-suited to the movie medium in many respects. For most people, these books are an audiovisual experience, as mom or dad reads aloud and points out the pictures.Their baby-dazzling techniques of bright colors and vivid locales and characters also match the basic cinematic thrill of looking at neat stuff.

Moments in “Curious George,” the new movie starring the H.A. Rey character, fulfill this promise of simple, joyful diversion. The movie’s opening is a plotless, wordless overture of George’s high jinks in the jungle. A typical bit has George playing with a chameleon. We watch George figuring out how the lizard changes colors, and then fetching different objects to produce a rug-sampler rainbow. When George later finds some unattended paints, it’s every child’s dream come true: a big, beautiful mess.

These moments capture the books’ mood of innocent wonder, but it is hard to make a full-length movie of this stuff without resembling an early-morning Nickelodeon show. Not surprisingly, the filmmakers of “Curious George” ultimately come down firmly on the side of old-fashioned plot.

The Man in the Yellow Hat, the monkey’s enigmatic handler, becomes the focus of the story, while George’s escapades, appealing as they are, become a sideshow. The plot is a tired matter of averting disaster before it’s too late: man and monkey must save a natural-history museum from going out of business.

The shift is understandable. Sure, the little guy’s cute, but for filmmakers the Man in the Yellow Hat has the double virtue of speech and being ready for a screenwriter’s makeover into a comic type.

As fans will remember, the books depict the Man in the Yellow Hat as a colonial adventurer of the sort all over children’s literature in the first half of the 20th century. A pipe-smoking father figure, he serves his purpose in importing the monkey and then hovers benevolently at the margins.

For our gentler modern age, he has become a likable nerd who lectures on dinosaur bones to children’s groups. Voiced by a surprisingly restrained Will Ferrell, he’s a good-natured schlemiel with the quasi-frustrated air of someone with a very cute monkey crawling all over him. (He’s also been christened Ted.)

But it means that the dreaded warm-and-fuzzies seep into both tiers of the feature. For the tots, there are George’s safely contained antics, while school-age kids and adults get the sensitive Man in the Yellow Hat’s museum heroics and bemused one-liners.

“Ted” doesn’t speak New Age, but some wretched scenes do occur. At one point he actually tells George that he’s not sure he can have a monkey in his life right now. It all reminds us that the success of children’s books lies in their simplicity – less is more. (The champion in this category is the “The Cat in the Hat” book, where the mother appears only as a pair of legs half off-frame.)

George, meanwhile, seems babyfied,”voiced” by Frank Welker through coos and gurgles. The script plays up the separation anxiety latent in the book, and the soundtrack of sun-addled pop by Jack Johnson drenches George’s every appearance in caring-is-sharing treacle.To give “Curious George” some due, it’s willing to poke a little fun at itself: The ancient Texan who runs the museum has a whiny son who resents Ted’s growing relationship with his dad. But voiced by, and physically resembling David Cross, he’s probably a joke lost on children.

At least the yellow hat remains very yellow, thanks to traditional animation that preserves the pencil-shaded look of the original. And the roll call of familiar episodes from the book is complete: balloons lifting George into the sky, splashy murals on apartment walls, and so on. But the teetering excitement so typical of the scenes on the printed page – a vortex of action around a sprinting fur ball – is lost. The filmmakers of “Curious George” would do better to embrace their inner monkeys, and play for play’s sake.