Light painting I think has been around for awhile but it's more of a hidden thing that many photographers still don't know about. I'm still learning it myself.
So what is light painting? Creating photos with light. Flashlights, glow sticks, led's, el wire, basically anything that is a light source can be used to help create a photo. It can be as simple as running a flashlight (or a colored light) over a dark object(s) or creating shapes and abstract designs.
You know how when you go to take a photo of Christmas lights or something like it but when you look at the photo the lights are blurry and are weird patterns? That is a form of light painting. It all comes straight from the camera.
Some people are very creative creating their light painting photos. They also get creative building their lighting tools. They take something like led lights and attach them to things that can be moved to make interesting patterns.
One of the neat things about light painting is that the possibilities are endless. No two photos are the same. It's really fun to see what you can create. There are lots of photos on google and how to videos on youtube.