Here are two of the books I made at the beginning of last semester in my bookmaking class, while we were learning the pamphlet stitch. The pamphlet stitch is one of the simplest bookmaking techniques, and I've used it before in both of these.
You can see in this second one that I've also included a tab on the back cover that folds over the front cover to clasp shut the book. Very cute and simple. These books were made out of recycled and found paper.