cheap and simple way to measure temperature

[ScaleRobotics]

Certainly not the cheapest, nor the most simple, but you can pick one up from Future Electronics for just under $10.00. The cool part about this one, is that you could have your POV clock sense a person in front of it, and have it do different things after sensing body heat, like saving your battery life.

http://melexis.com/Sensor_ICs_Infrar...O-can_685.aspx