So my four-year old daughter is currently obsessed with the Nick Jr. TV show "The Backyardigans
." It's easy to see why; the show is utterly charming, even for a jaded viewer like me. Five animal friends (a moose, a penguin, a hippo, a kangaroo, and one undefined "unique" creature named Uniqua) have adventures in their backyards which morph, Calvin-and-Hobbes-style, into jungles, Egyptian pyramids, medieval castles and so on. The CGI animation is pretty but rather soulless, but it works.)
The real anchor is the music (and the excellent voice acting), which is just superb for a kiddie TV show: incredibly catchy children's ditties that are the functional equivalent of Broadway showtunes -- each song within the show is totally choreographed, with dancing. The songs are thematically coherent for each episode, but across the series the music runs the gamut from reggae to rockabilly to country to Dixieland to James Brown funk.