Music made for kids is the absolute worst. As much as you might try to raise your kid on a diet of Dinosaur Jr and the Ramones, eventually a grandparent ruins everything with some Disney Princess nonsense or the Wiggles. Sure, there are children's albums out there by They Might Be Giants and the Fun Fun Records roster is actually good, but they are the exception, and the rule is Raffi.
Right now for free you can download a 3 song sampler on Noisetrade for Sandra Boynton's FROG TROUBLE. If you have a kid, you know Sandra Boynton's surprisingly good books featuring animals in people clothes (But Not the Hippopotamus is my personal favorite). FROG TROUBLE is a collection of kids' songs written by Boynton and sung by a mixed bag of artists. You'll probably want to focus on Ben Folds, Ryan Adams, Mark Lanegan, and Fountains of Wayne while ignoring Darius Rucker. The "fun pack" you can download for free includes Kacey Musgraves, Ryan Adams, and Ben Folds. Ryan Adams' "When Pigs Fly" is much better than it should be, and could actually fit in with his own songs.
You can download the FROG TROUBLE Fun Pack here, and watch a making of video below.