This house...has a small backyard, so the parents built slides and secret passages within the house that the children can use for play. There's a slide from the first floor to the basement, rock climbing walls in the basement, a secret passage to the attic from the childrens' bedroom, a shaft from the basement to the attic and other neat features. [and hallway monkey bars, like I want to build!]
Any slide for adults in a house is a great idea, but this one contains a water slide. Excellent choice of transportation and you can even get a shower on the way out of bed going down to get breakfast!