What do four pencils, tape, ball point pen, rubber bands, and a bamboo skewer equal? An obligatory safety warning, that's what.
Actually, it equals a mini-crossbow built from office supplies that COMES with an obligatory safety warning, which is simply this: don't be an idiot. Now to the fun part.
Straight from John Austin's Mini Weapons of Mass Destruction: Build Implements of Spitball Warfare, this office supply crossbow seriously looks like something that can actually stand up to some repeated (safe!) firings.