Water Drums are simply half-calabashes (gourds) floating in water. They are played extensively throughout Africa and the Americas, as well as in the bathtubs of Percussionists Who Have Everything. The money is used to patch cracks in the material because it has a high rag content giving the repair greater durability. It's also nice reminder that everyone has the potential to be a millionaire at least once in their lifetime, depending on the currency in use.