Artists Taiyo Onorato and Nico Krebs create homemade cameras out of bizarre objects such as turtle shells and large stones. The large format camera above was crafted out of a stack of photography books. Their experiments are documented in a book titled As Long As It Photographs It Must Be a Camera. You can find a recent interview with the artists over at American Photo.
Turning Turtles Into Cameras With Onorato & Krebs (via Photojojo)