Mobile home. On the road, it measures m by m, and once it has arrived at its destination its floorspace can be increased threefold in a matter of seconds. "De Markies" was awarded the Public Prize at the Rotterdam Design Prize
Really Fun Library Slide - Architect Moon Hoon designed the Panorama House in South Korea, which features a multi-functional library. A wooden slide (used by the adults in the home, too!) is flanked by stair step bookcases.
A slide in Maison Martin Margiela, Sanlitun Beijing! I want one in my dream house - maybe from the front porch to the bus stop for my kids (and for mommy when she goes to pick them up ; This looks like so much fun!
House in a Box: Move fireplace to livingroom/porch corner and make a passthrough fireplace. No up stairs - just tall ceilings with windows for light. Wrap porch all the way around to bedroom and add french doors.