Arthur (http://pbskids.org/arthur/index.html)

Arthur the human-like aardvark plays out well on the Web. The site is full of age-appropriate games that fans of the cute creature -- and those who've never even watched the TV show -- can get into. And the best part? The games are actually teaching your kids something. The Music Box might be the most unique part of the site as it combines music and learning, so much so that kids won't even realize that they're figuring out space relations, hand-eye coordination, and mousing skills as they jam along to upbeat tunes.