Looking for a weekend project that'll get you a little closer to being like Batman? Well, why not turn a fire extinguisher into a fully functioning grappling hook launcher?
All you need is a fire extinguisher, a Nerf gun, and a bunch of miscellaneous pipes, hoses and assorted doodads. You'll also need to know how to solder copper pipes, but hey, how card can it be? It's certainly worth learning, as once you know what you're doing you'll be able to build a grappling hook launcher. I mean, come on, how many other skills have such immediate rewards?