Dishwashing liquid (Joy or Dawn), water, glycerin (can be found at a drugstore)
Mix together 2/3 cup of dishwashing liquid (Joy or Dawn work best), 1 quart of water, and 1/3 cup of glycerin. Stir with a whisk to combine all ingredients. Then pour a small amount of the liquid into a bowl or bowls for the kids to use. Use your imagination when finding bubble makers -- plastic berry baskets are great for making lots of little bubbles and wire hangers can be bent to create great big bubbles!