All you need is a zip-lock sandwich bag and a paper towel as well as the Baking soda and vinegar: (Do this experiment outdoors or in the kitchen sink and always wear safety glasses!)
Place one tablespoon of baking soda in the center of a paper towel, fold up the towel into a square package with the powder held inside.
Into the zip-lock sandwich bag add 1/4 cup of vinegar. Put the paper towel package into the mouth of the zip-lock bag and hold it out of the vinegar by pinching the sides of the plastic bag. Zip the bag closed with as little air inside as possible, then let the paper towel drop into the vinegar.
The bag will fill up with carbon dioxide gas, if too much gas is produced, the bag will pop (explode) with a bang. If this happens, repeat but reduce the quantity of baking soda.