A laid-back surfer who makes everything look easy turns out to be the perfect musical alter ego for a pesky monkey who’s always in a jam. Who knew? While nothing in Jack Johnson’s previous work evoked anything nearly as kinetic as Curious George, the singer-songwriter’s songs have an innate playfulness — and an abiding sense of wonder — that make him a natural for children’s music. Though come to think of it, only two or three of these are children’s music at all. “3Rs,” for instance, gives an eco-friendly twist to the Schoolhouse Rock classic “Three is the Magic Number,” while “The Sharing Song” delivers an age-appropriate lesson in an upbeat surfer-dude way: “If you’ve got a ball/ Bounce it to the gang/ If there is a new kid/ Invite him out to hang.” But most of the other tunes here would sound perfectly at home on any of Johnson’s previous three albums, including the infectious shuffle of “Upside Down,” an irresistible, radio-friendly tribute to the monkey (and the kid) inside all of us. A cover of The White Stripes gem “We’re Going to Be Friends” fits the mood perfectly, while the delicate ballad “Broken” could be about a lover, could be about the Man with the Yellow Hat, and hey, does it matter? This is music for both preschoolers and parents to enjoy, a perfect companion to the film’s gentle sweetness.