I remember taking my first photography class, in like 7th or 8th grade. One of the very first projects that we did was make pinhole cameras. We spent one day making the cameras (out of shoe boxes), then the next day wandering around campus during the entire period capturing images with them. We were exposing directly to photo paper, so everything was a negative. But I still remember how much fun it was.
Enter the paper Leica m3. How awesome is this? I would say that it is quite an upgrade from the rickety shoebox contraption that I built back in the day. This printable papercraft Leica m3 was designed by Matthew Nicholson, and is available for download from his site for only £1.50. It comes with assembly instructions (which appear to indicate that it shoots 220 medium format film [same as the Holga]). I think that I may have found a project for the weekend. A few more looks below–