As explained by the Duke Center for the Study of the Public Domain, today is Public Domain Day! Since the copyright term was extended in 1998, old works haven’t been entering the public domain regularly, but we just reached the end of the extension period. Much text, art, and music has been freed.
I cheerfully recommend Carl Sandburg’s charming stories for kids, collected in Rootabaga Pigeons, and P. G. Wodehouse’s first Jeeves “novel,” The Inimitable Jeeves. The latter is comprised of previously published stories but is delightful even if you’ve seen them before.