Face it, guest books are boring.
I ran across this very fun idea today that you might like.
This one was done by having the guests put their fingerprint on the tree and then add thier name. It kind of oooges me out to think of my guests having to be fingerprinted for my wedding.
Here is another idea that I think I like better. Get a line drawing or painting of a tree with out leaves
Then get either die cut leaves from some where like Paper Source , Hobby Lobby or Micheals or get a paper punch and make your own and have your guests sign them.
You could get some pretty baskets or glass bowls to fill with leaves and a pen and use them as parts of your centerpieces. Put another on with the tree picture and a small sign explaining the idea.
Once the wedding is over, put the leaves on your tree. Frame it and you have a piece of art to treasure for ever.
Or you could just have a boring book you won’t ever look at again.