Sharpen your library skills by "shelving" fiction and nonfiction books.

A variety of content across all academic areas.

A great resource for upper elementary students sponsored by the National Endowment for the Humanities.  Provides web access to some of the worlds great museums, libraries, cultural institutions, and universities.

Fact Monster is a kid-friendly source that with features including dictionary, thesaurus, encyclopedia, atlas, and more!

Aside from the wonderful access to the dictionary, this site offers words games and a word for the day

Pitara is a great site that includes biographies for kids, as well as science articles, stories, poems, and fun quizzes.  (Link is to the Biography page.)  

Kid-friendly word definitions.