Gum and Chocolate is a fun (and gross!) activity in which participants can experience a chemical reaction in their mouths. This activity involves real gum and real chocolate, which could conflict with your organization's policies around food, allergens, or chokeables, so you may want to use the activity only for facilitator training purposes, or at a closely monitored table at your event.

http://nisenet.org/catalog/gum-and-chocolate-training-guide-and-materials