I have my own document camera in the classroom, but I wanted a way to help students out from my home. Following this guide, I rigged up my own using a webcam, a gooseneck mic stand, and a few zip ties:
Pretty cool, yeah? The image looks flipped when you see it on your own computer (humans like their own webcams to appear as mirror images), but normal to anyone on the other end. If a student asks for homework help, it's great to be able to get them on Skype or Facebook chat to demo a problem.