Making your own macro lens mount

We know a young man who likes the idea of building a telescope lens from scratch - grinding and polishing it and everything. There is, after all, a satisfaction in making something yourself.

jquinby's project isn't quite that time-consuming (he claims it took about 20 seconds), but he's now taking macro shots with his digital camera, using stuff he had on hand. I can think of some folks around here who would have fun doing the same thing. (Hide the telescope! Scavengers ahoy! :)