A lot of people use cardboard in their arts and crafts, but Kiel Johnson took that into a whole 'nuther level with his cardboard cameras. This one above, the iconic twin lens, even works as a pinhole camera.
See more of Kiel's cardboard camera over at OddityCentral: Link | Kiel's Website | The Twin Lens Reflex, a video clip of the making of the camera above.
-Murk