Adults need to have fun too! 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!
So much room for activities. but little, individual reading/working nooks (for a tea house or library.) -- or just a space to crash/decompress/work in a different position. And the scene from step brothers makes it even better!