Laurie Lawlor has collected 26 (one for each letter of the alphabet) hilarious similes from American folklore for her book, Muddy as a Duck Puddle and Other American Similes.
A couple of my favorites were "Jittery as a long-tailed cat in a room full of rocking chairs" and "Ugly as a mud fence dabbed over with toad frogs." Ethan Long's funny illustrations help the reader understand the meaning of the similes. The best part of the book is the author's note where Laurie Lawlor gives interesting information about each simile. This book should be added to your collection of texts used to teach figurative language. It would be a good companion to books such as Fred Gwynne's The King Who Rained that are wordplay classics.