I think all of the Scarlet Pimpernel series is on Gutenberg.
Breezy and fun; they've have aged well if you don't mind the occasional ethnic stereotype. You don't have to know anything about history but some of the fashion terminology takes looking up, if you want to be really sure what kind of lace you're imagining.
Rootabaga Stories. It's a book of American Fairy Tales, written by Carl Sandburg. If you've never read any of his other works, I would recommend them, as well.
How can you be a potato bug millionaire if you don't have any fleems?