I have a fascination with nixie tubes, or vacuum tubes that ThinkGeek calls the LEDs of the past. These tubes aren’t being manufactured any longer, but there are still some available that are being used to make Steampunk things like clocks and thermometers. You’ll need to know how to read schematics and how to solder electronics, but you’ll be able to build a thermometer that displays temperature in Fahrenheit, Celsius, or Kelvin, and shows humidity with this DIY Nixie Tube Thermometer Kit. The microprocessor-controlled thermometer has a rear temperature sensor, blue LED accent lights, and a motion sensor to change the display. The kit contains everything you need, including a case with brass hardware and a power supply. The DIY Nixie Tube Thermometer Kit is $179.99.