take a penny, leave a penny
I recently stumbled upon a guerrilla back alley library about a block away from my apartment. It was full of odd titles, mostly romance novels and soviet tracts, but sprinkled liberally with terrible summer beach books, too, the sort you buy at the airport for the flight then never read again. I borrowed a copy of The Third Policeman and left behind A. A. Milne's Now We Are Six, one of my favourite books from early childhood. If you would also like to donate, or even just browse, it can be found in the alley between Francis and Pender, a half block west of Commercial Drive.