Baking soda and vinegar balloons

This was our highlight of the evening. It was baking soda shoved in a balloon (a funnel would have been great but I don't know where the kids placed it when they did the dishes last). Them a bottle of vinegar. We placed the balloon over the lid and dumped it in. The reaction started happening immediately and so did the balloon filling up. The kids wouldn't stop asking for an encore!