Ahh, another hot night in the Valley. Too hot to sleep, the heat and the beer must be getting to me. I don't know why, but I made a very cheap laser/IR detector.
Well, I was going to post a pic of my achievements, but I can't at the moment.
Imagine a bread board, 4 AA batteries, a 270 ohm resistor, a green LED and 1 infrared detector. Shine a laser at the detector and the LED lights up. The intensity varies, depending on the angle.
Useless, but provided some entertainment this hot night.
P.S. I'll post a pic of my wonderful device later...