A conundrum is a puzzle, a puzzle that's a conundrum. But what if we sorted them by number? Here's a conundrum for you:
A man walks into a library and asks the librarian, "I'm looking for a book on 'Pun-ishment'." The librarian replies, "I don't have any books on that subject, but I have some on 'Dolmenship' and 'Fumbleness'."