My own "smart" Christmas decoration that I made with some LEDs, a microcontroller, and a ceramic Christmas tree decoration. It uses a simple circuit with two MOSFETs and an ESP8266 to control the lighting. This is also written with the nodemcu firmware in Lua, but I had to use some tricks to get the memory usage down using the Lua Flash Store. You can find the source code here. It requires a specially configured build of the lua compiler which is configured to use the LFS. You can find out how to do that on the NodeMCU website.

Here is a picture of the finished board

And a video of it in action