The generally accepted term is "light painting", and we have a few practitioners right here on the MR photo forum. A
Google search will show you just how creative some folks get with this technique. My own take has been on a larger scale, generally four strobes and a flashlight or two, all gelled and aimed at large-ish structures. We usually have a couple of the strobes on stands, triggered remotely and fired repeatedly, and then a couple of strobes plus a flashlight or two in the hands of two people running around the scene "painting" as quickly as the strobes can recycle. See my "Glowing" gallery for some of the resulting shots.
It's great fun to play around with lights and long exposures. My general advice to anyone getting into it would be to remember that light painting photos should aim for the same kind of balance and harmony you would see in any natural light shot: try to avoid crushed blacks and blown highlights, strive to achieve a full range of tones, and (of course) keep in mind everything you know about what makes a compelling pictorial image.
Anyway, if you've been at it for a while, definitely keep 'em coming in the PotD thread. You'll find a very receptive audience here.