Zags was just short for zig-zags.

Alright I'll tell ya how I made one of the dozens of bongs I've made. It's simple as hell if you know basic bong principles. Just grab a plastic bottle that's the right size for however big you want your chamber to be. 20 oz, 1 liter, 2 liter, etc. The stem and bowl are going to have to be improvised using whatever you can find in your house. For the stem, a hollowed out pen will do. Take the plastic with the ink out of it, and the actually writing part and the bottom. Some people find metal stems to use. Now you need to find something suitable for a bowl. This is the hardest part for me to find. Do you smoke cigs? A lit cig will burn the perfect sized hole for your stem to go into. Burn the hole in the side of the bottle low enough for the stem to reach the bottom and be pointing upwards. I think I actually took another hollowed-out pen and cut a third or so off of it, and hot glued it to the top of the other one before putting it in the bottle to make it longer. Now grab your bowl (Don't use a plastic bottle cap god damn it! I had a friend do that. Ewch), and attach it to your stem somehow. If you're anal-retentive like me, you're going to want that shit to be airtight. I can't STAND if it's not airtight. Take hotglue or gum and patch the chamber a little to kill those little holes. Now with your cig, burn another hole on the opposite side of the bottle from where the stem hole is. That's your thumb carb. Now toss the water in the bong, bud in the bowl, put your finger on that hole and spark it.

There are many many many threads on homemade bongs on this site. You'll find more detailed and ingenious ways to make some creative bongs. Get searchin'.