Been messing around with an Arduino microcontroller. I wanted to figure out what the temperature in my room was, but I didn't want to have it hooked up to my laptop all the time to read the output, and I don't have an LCD display. So, improvising, I programmed it to light up green when it's 68 degrees and fade the red LED low to high the higher the temperature above 68, and fade an RGB LED blue, from low to high as temperature decreased below 68.

Pretty simple but neat.