This website shows you how to "hack" off-the-shelf Christmas lights into an interactive light show!  

It uses free software and low-cost hardware to make this possible.  The software is called xLights which provides professional light animation.  The hardware involves a mixture of Raspberry Pi microcomputers and Arduino microcontrollers.  

The result is a universal system for animating your Christmas lights that can easily grow into fancier displays in the future.

While you can use a computer running xLights to run your light show, it is also possible to enhance your system to allow Internet control of your lights!  People from all over the world can view your holiday display and change the animations.