Do you know about the Little Free Library? This is a great idea where someone builds a small structure to hold books that neighbors can bring a book to add and/or take a book to read. Read more about it here on the Little Free Library website. They have tips on how to build your own (and ask you use recycled/found materials) and you can register your Little Free Library on their map.
I like the knob on the one above. If you do a image search you can see how creative people were in building their little library.
I like how this one re-used a newspaper box.
Anna would like this one.
And this one is really outside the box, so to speak.