Bring all kinds of disgusting challenges for the children to face. For example:
Eating a diaper full of poo (baby diaper with Nutella)
Eat frog eggs (tapioca pudding with green dye)
Find a key by plunging your hands into a jar that contains grasshoppers
Make the analogy with the fact that often we are afraid because we rely on what our eyes see. A courage like Joshua’s is not the absence of fear, but trust in a God greater than all the challenges before us.