I assembled a geeky new kit today. It displays the current temperature in Fahrenheit or Celsius in binary format.
The kit takes about 20 minutes to assemble and solder, and the instructions are really easy to follow - recommended for any beginner.
It's PIC controlled, so in theory it could be reprogrammed to work in a different way.
Link to the website: http://maximumoctopus.com/electronics/dbinarytemperature.htm