We've previously mentioned the Little Free Library project. It's a program that encourages people to build small covered boxes with books available to anyone who passes by. Just leave one and take one.
According to internet rumor, this is one that can be found in Madison, Wisconsin. So go take a book and leave a book. Be aware that the only ones currently available for check out are not exactly heartwarming stories.
-via Edda Thornton-Verma