Video: Looking for one last DIY project before the holidays? Adafruit has a guide for making your own 8-bit Super Mario tree topper using an Arduino, LEDs, and a few other tools. You'll need access to a 3D printer for this one, but beyond that, the electronics and coding are pretty easy all things considered. Either way, it's worth the effort considering you'll have the coolest tree topper around.
Starduino: 8-Bit Super Mario Tree Topper [Adafruit]