Check out this video from Chemical Reaction Tutorials (CRTutorials). If you love filmmaking, prop making, editing and everything else that goes along with making movies, then you'll want to see what Adam has to say about laser guns.
Adam explains how to build a laser gun prop and create laser effects. You can make this nifty laser gun weapon prop with items laying around your home. To make the laser shooting effect, you'll need Windows Movie Maker, Gimp, and Monkey Jam.