I've always thought of the idea of doing a messy game show at home (subject to me getting the house to myself). The two rooms which could be used are my bathroom and a downstairs space, which isn't visited often. Plus, I have access to a drain that I can chuck excess gunge down. These challenges I would set up, will be as inventive as possible but in budget and suited to the surroundings. I've already thought of the final round, an overhead gunging using balloons.