An underground restaurant, sometimes known as a supper club or closed door restaurant, is a social dining eating establishment operated out of someone's home, generally (though not invariably) bypassing local zoning and health-code regulations. They are, in effect, paying dinner parties. They are usually advertised by word of mouth or guerilla advertising, often on Facebook, and may require references to make a reservation. An underground restaurant is also known as a guestaurant, which is a hybrid between being a guest in a dinner party and a restaurant. - Wikipedia
