Warbow

(Sorry for the blurry pictures, it's not very easy to aim a camera that's part of your watch.) Not technically a crossbow, but it's based off the Heavy Crossbow's barrel and trigger. This is not your secondary war weapon. Nor is it your primary. This is your "I'M GONNA FREAKING KILL YOU FOR WHAT YOU JUST DID" gun. It moves a red rod with a grey on one end and a red with a green rod on the other faster than my eye can follow. It doesn't have particularly long range as far as I can tell, but that's because my room isn't very long. It did, however, put a good size dent into what is for other things a nigh-indestructible door with the lightest ammo that it can fire.  I'll post this if enough people want it, which I place at about three for a slideshow showing how the insides work and six for an actual 'ible. Please note that this thing is too complicated to build from the pictures due to the casing of the mechs and the unique way the barrel is made.
EDIT
Posting tomorrow, have pics. Also has a just-implemented third firing mode, "booby trap", which holds the front trigger at its extreme forward and when the pin is pulled allows the trigger to shoot backward, firing the gun. Basically a game breaker, because it'll end up shooting them in the soft part of their side if it's at a proper height to be set off by walking.