Dry Ice Bubbles
Stir up some bubble, bubble, toil, and trouble using dish soap, water, and dry ice. For safety, keep kids away from dry ice pellets, which are extremely cold.
Source: Martha Stewart
Dry ice available from your local ice distributor or for free as part of your frozen steak (or specialty food) mail-order packaging.
Tall cylindrical container
Dry ice pellets (or pieces of a block)
Concentrated dish soap
Fill bottom 1/4 of cylindrical container with water.
Add pellets/chunks of dry ice to water.
To create bubbles, add 1 teaspoon of concentrated dish soap (or more if desired) to water and dry ice mixture.