We pointed out this great Instructable on making LED light drawing pens a while back. Stuart and Lori have a really neat tutorial about light drawing on their site, LightDoodles. (I’ve always loved this picture of Picasso.)
Light doodling or light drawing can be described as the simple act of capturing the trace of a narrow moving source of light using long exposure photography, long being defined as seconds or minutes. The moving light source will then appear in the finished picture as more then what actually exists and is truely a representation of time as well as space and movement.