Make your own tumblers from wine bottles using a simple tool which you can purchase online for under $50. I'm sure there are all kinds of applications for this, starting with some awesome tumbler cups. All you have to do is score the area you would like to cut in a straight line using a special tool, immerse the bottle in alternately hot and cold water, and the wine bottle cuts where you scored it. More info after the jump!
Green Power Science sells the tool, and provides a video on how it works.
(image: Green Power Science)