Beyond the Sky

Remember starwars kid?
He is the first one who start video shot himself playing "lightsaber"

Nowadays, technology is so advance, you can put yourself into lightsaber virtual fight, check this three out.
http://www.youtube.com/watch?v=0dykGRGzzVA
http://www.youtube.com/watch?v=jUBUtZranpE
http://www.videosift.com/story.php?id=630

There are more, and there even have video tutorial showing how to make those "lightsaber" effects.
http://www.metacafe.com/watch/400298/how_to_lightsaber_effect_video_tutorial/