Quite a few years ago I think I joined the online Book Crossing. Never did anything about it apart from look at the website.
We were on our way home walking along Toorak Road and R stopped to pick up a book off a public bench seat. It had a Book Crossing sticker inside the front cover. We went to the website and logged the details.
To save you the bother of looking, you join the site and print of a sticker to put inside a book and leave the book in a public place for someone to find and hopefully read. When they do, they enter the details at the website. Kind of like an informal book exchange. Once you have read the book, the idea is to leave it somewhere for someone else.
Book Crossing has no borders and books can travel around the world. Nice little scheme and for a change, no money involved.
Pity I got rid of all books I don't want to keep, or I would start leaving them around.