For just a couple of bucks and a few components you have laying around your work area you can build a min thermometer than fits in your pocket. The whole circuit sits nicely right on top of a 9v battery, and is connected to it with double sided tape. Changing batteries was never so easy!
I hope you enjoy the project and vote it for the contests!
Step 1: Mini Thermometer Demonstration
In case you were wondering why the LEDs are flashing multiple times on each flash it's because I'm using PWM to power the pins.