Disclaimer: I don't have a juicer.
I saw a blog post recently where someone had used the pulp from their juicer (combined with some other things?) to make fruit leather. Pear-ginger-carrot leather, I think it was?
I would think you could also dry the fruit to add to oatmeal etc. (I'm thinking apples, pears here).
Would be neat to see how/if someone tries that.