We've previously seen a house that was plumbed with beer. The advantage to this household feature is that you've got beer flowing through every tap. But you may not want to drink or bathe in beer all day. For example, if you're getting ready for work or school in the morning, beer may not be the ideal beverage choice.
Coffee works better. So Teddy Wilson and Norm Sousa of the comedy/reality TV show Never Do This at Home turned a home water heater into a 40-gallon coffeemaker. They used instant coffee, which is not ideal, but it's a step in the right direction. Now it's possible to take a bath in a tub full of coffee, which is something that I've always wanted to do.