I have two ideas that I've done before:
1) Tear out pages of pictures that are really pretty and frame them to keep or give as upcycled gifts.
2) Shred the pages and use as hamster/animal bedding for their cage or if you don't have one put it up on Craigslist as free animal bedding.
3) Put them up on craigslist for free, maybe someone else has ideas.
4) Donate them to a school to use for paper mache projects.