I found some GREAT D.I.Y. camera sites!

Yes. It is possible to create your own camera. In fact you can either make a large-format camera out of wood, aluminum and cloth or you can just go straight for a paper pinhole camera (using 35mm film) that you cut from sheets of printed paper and glue onto card stock to fold and tape together. Here's the link for a large format camera by Ed Hoover: Ed Hoover's Econon LF Camera. However, I think the most fun can be had by doing the colorful camera from Lighthouse in a Tree (Linatree). They've put together an Adobe PDF file which you can download for free, print onto normal paper using your color printer, glue onto the - thin, because you'll be folding it - black card stock using some of that Scotch 77 spray adhesive, cut out with a craft knife, fold and tape together. Here's the link:Linatree Paper Pinhole Camera. It's blocky, it's red and it's just too simple to pass up!