I bought a really small video camera on Amazon recently...

http://www.amazon.com/gp/product/B00...UTF8&psc=1

It's 5 x 2.5 x 5 inches and weighs under half a pound. The audio's not great, but it clips to my shirt or vest and does good video. Now I can go crazy like those guys on American Diggers when I find a manhole cover, or something.