It's called light painting, if you have a DSLR, you can do it yourself, all you need is a light source (cell phones work just fine, but I've used a weak flash light here). Basically, you use a long exposure and "draw" with the light source.
As you can see from the statstics at the bottom right, the exposure is thirty seconds and the apeture is f/22. When it's that dark, only light will show, unless I stand quite still (which I did not ).
You can read more about how to do it here: [link]