I still have some of that really lovely hand-made paper with leaf inclusions I found in Mexico at--surprise!--Office Depot. The cover of this book is one sheet of that paper, 8 1/2"x11" cut in half. The text pages are some pale green speckled recycled paper, also found in Mexico.
I've had these old skeleton keys lying around for quite awhile, waiting for the exact project to come up. They were perfect for this book. Each rubber band comes up through two holes from the back of the book and loops around the one of keys, holding the pages together.
This would make a lovely housewarming gift or a guest book for one's home.