If you don't have anything to do this weekend and also have an extremely chill landlord who doesn't care if you construct a weapon using highly flammable materials, there's always the option to build this elaborate propane prop gun using an empty pop bottle.
(Or you could do anything else. This shit looks incredibly dangerous.)
YouTube user NightHawkInLight provides the instructions on how to make the cool-looking but horrifyingly unsafe prop gun. "Don't point this at anyone" is one of the more salient points of the tutorial. He used a Bernzomatic TS8000 torch, vinyl tubing, and probably a fair amount of chutzpah to put together the prop gun. Instructions were originally posted for the project on Instructables.com.
It's like they say: Life's too short not to test its span with ill-advised DIY art projects involving shooting fire through a tube until it creates an explosive noise based on a YouTube video dictating instructions using the passive voice. [YouTube]