Here's a very simple, but a stunning little gizmo which can be assembled in less than 30 minutes. I show you how to build a simple Infrared cam that can see-through certain materials and also has night vision capabilites! All you need is an old webcam/digital cam. (The process requires ripping open the cam and altering its lenses and all. So ONLY use an old cam or something). I've also included a few pics I shot with my modded Logitech Quick cam.

Here's the article:
http://kailashnadh.name/docs/ir_cam

PS: Please do this at your own risk. I won't be responsible for the damages you do to your cams, if any!