"Wings" is an amazing book with behind the scenes photography of Cirque du Soleil. Veronique Vial traveled with the circus for years, and compiled her photographs in this book. Some photos are as strange as you would imagine, but my favorites are the more candid shot of performers practicing or getting ready. It is an excellent source of inspiration. Not only is the subject matter bizarre and incredibly interesting, but her photographs themselves are gorgeous.
Anyways, here is a clown. If you own the book you can see where the reference came from :)