1) Cut off the bottoms of 2 or 3 lunch bags so there are openings at both ends.
2) Stack the bags on top of each other and fold in half. Secure the binding with staples or punch holes and tie the bags together.
3) Slide index cards into each pocket.
4) Write and decorate the book with whatever skill or theme you'd like.
I thought they could be used for moon phases, vocabulary, synonyms, antonyms, math story problems, etc. What else can you think of using them for?