They wanted 3 pretty common hacks to the cameras: Pinholga, 35mm Conversion, and attachment lenses.
The Pinholga was the most fun:
and the resulting images...
Ode to Niepce
Then, the more common 35mm conversion:
Because the camera wasn't visibly changed on the outside, I decided to paint the body gray while using pieces of film to mask the paint.
Very fun results.
Gratuitous self portrait
The attachment lens wasn't so much a "mod" as it was just collecting old filters from local camera shops. I threaded and glued a 46-49mm step-up ring into the Holga lens, and then just attached filters. Everything from magnification, cross screen, color correction, diffusion, and more. I was able to fit a camcorder telephoto lens on it as well using a 49-37 step-down ring.
Some really great effects!