We had a book exchange where everyone came with a wrapped book that they had already read at home and were willing to pass on.
Then I invaded my scrapbooking stickers and pulled out all my pens, markers and stickers and they made bookmarks. They did that at the table for almost an hour!
We of course did the usual cake and presents and then everyone went home with a gift bag. For those I took an old book and ripped out pages, wrote the first letter of everyone's name and glued them onto brown paper bags. I filled them with a little baggie of gummy "book" worms, pencils and little notebooks I found of sale. I had also made stickers for their books with "This book belongs to" and forgot to put them in the bags. Majorly mad at myself the next day! Here is were there is a template for those or make your own using shipping labels. This site had a lot of cute ideas.