When Charles Rivkin became head of W!ldbrain in 2005, the Jim Henson vet wanted to make a statement. He started with punctuation (hence the "!"). Since then, W!ldbrain's Sesame Street -- like flagship series, Yo Gabba Gabba!, has done wonders for Nickelodeon, averaging 3.4 million viewers and luring guests including actor Jack Black and the band the Ting Tings. It will soon air three times a day on Noggin, Nick's pre-K channel -- huge exposure for a show the network doesn't own. It has spawned a live tour, and a movie is in the works. Meanwhile, W!ldbrain subsidiary Kidrobot -- maker of edgy figurines such as Labbit the smoking rabbit -- has earned a cult following among millennials and gen-Xers. We'd call it child's play, except for the seriously grown-up profits. -- by Dan Macsai