Okay so this one time me and my buddy were getting drunk, and we got into the garage and started rootin around looking for anything cool and we found one of those little gas-mask breather things you use while painting er whatever.
So it was set up to where you can only inhale through this hole on the front of it, and only exhale from the hole on the side; no air goes out the front hole, no air comes in the side hole. What we did was we made a regular ole water-bottle-pipe (not a bong) using a rubber elbow and a socket, and then sealed the mouth of the bottle to the front of the mask with some handy dandy duct-tape.
Thing was beautiful, and would choke any motherfucker out that went longer than a couple puffs-- you could really sit there and just suffocate yourself with bud smoke, because you could only inhale through the bowl.
Best thing I ever did while drunk.
NOTE: the front hole of the mask had a filter in it (obviously) and we removed that.