Donate them! Look for a local cloth diaper bank or charity that can use them. There are also some other organizations like Giving Diapers, Giving Hope or Share the Love.
Pass them on! Do you have a friend that could benefit from using cloth diapers? What about someone who has crossed your path that may be struggling to provide for her baby? Sharing your cloth diapers with others may be the best thing you can do with them!
Sell them! Recoup some of the money you spent on your diapers and sell them! You can use a site like Cloth Diaper Trader to list and sell your diapers.
Repurpose them! If you have a ton of flats, prefolds or microfiber inserts, use them for cleaning rags around the house! With kids, you can never have too many towels to clean up spills! Another idea is to let your little one use a diaper cover on her dolls.
What do you plan to do with your diapers when you are finished with them?