I thought, for a moment, I'd put this in Advanced Technical Discussion on principle.
(I postulate that there is some pretty high-tech laser technology hidden in here somewhere, but I think the creators have left out just enough that we won't be able to recreate the effect illustrated in this video..)
Anyway, this is good stuff:
http://www.newgrounds.com/portal/view/195918# (Click on WATCH THIS MOVIE!)