Easy PVC Pistons + Simple Airgun by fozzy13

Garden Hose Water Gun for Hero Dads by bgepp1

Build your own Aperture Science Portal Gun by ThePropNerds

Easy $5 Water Guns by seamster

Steampunk Gatling Gun Arm by V-Man737

Air Powered Potato Cannon by Hermes

Blow Gun & Darts (video included) by aliyevzaur1989

Bolt Action Blowgun by pie R []ed

Air powered PVC water bottle launcher by Whitedude0728

Airsoft M72 LAW rocket launcher by MrTinkerer

Proof Of Concept Valveless Air Canon by aaon

Easy Nerf Blow Gun for Hero Dads by bgepp1

Make Your Own Shuriken Throwing Stars Our of Paper, CD's,… by tinglystix

Egg Cannon by boston09

The Humidifier: aka the latex powered water gun by Kaelessin

cheap, affordable and fun... MARSHMALLOW GUN!!!! by benpic10

blowgun and darts by ostomesto

How to make a paintball silencer by MrAngryPants