The princess test / Gail Carson Levine. In this humorous retelling of Hans Christian Andersen's "The Princess and the Pea," Lorelei must pass many difficult tests in order to prove that she is a true princess and win the hand of Prince Nicholas.
The fairy's mistake / Gail Carson Levine. A retelling of "Toads and Diamonds," the fairy Ethelinda rewards one twin sister for good behavior and punishes the other for bad, only to discover that her punishment is more pleasing than her reward.
Any Gail Carson Levine books. I actually have a lot of her books and have had them for a long time, but the only one I have read is Ella Enchanted because. Saw the movie. And they were completely different from each other.