This 5 gallon jug was simply filled with 25 pounds of dry ice, plugged up with a screw in pipe sealer, and then left for about 30 minutes out in the summer heat. What fun! Just don't stand to close when you try it. This video was taken from behind a completely closed sliding glass door. Notice how loud it still is. It is great fun, but don't try it unless you plan on being very careful. This was done in the summer of 1994, a very long time ago, so don't hold it against me too much :)