PHOTO + VIDEO : Billionaire Bill Gate Multi-Millionaire House

Software tycoon Bill Gates turns 58 today. Because he's the world's richest person, having recently reclaimed the title from Carlos Slim, according to Forbes), you might expect him to have some pretty impressive living arrangements -- and guess what, you'd be right.

He built his 66,000-square-foot main residence on Lake Washington in Medina, Washington, over the course of several years. It was assessed this year (and the three years before that) at $120.6 million, down from a 2008 high of $150 million.

Some time ago, U.S. News & World Report ran a fairly extensive article plus slideshow(with renderings, not photos) about the home. But Gates -- who was originally quite voluble about the home -- hasn't talked much about it since. Among its unique features:

• A 2,100-square-foot library has secret bookcases and a dome with oculus. The ceiling is engraved with a quote. "He had come a long way to this blue lawn," it reads, "and his dream must have seemed so close that he could hardly fail to grasp it." It's from "The Great Gatsby."

• It has a pool with a "fossil motif" floor. You can swim under a glass wall to emerge near a terrace outside.

• Only about 20 percent of the home is family living space, including four bedrooms and nanny quarters. Much of the rest of the square footage is given over to a reception hall, offices, conference facilities, a computer room and other gathering spaces.

• The compound has seven bedrooms and 24 bathrooms -- and six kitchens, presumably because the home hosts receptions and conferences.

• It has a "trampoline room" whose ceiling is 20 feet up.

• "Miles of communication cable, largely fiber optic, run throughout the house," U.S. News reported, "linking computer servers powered by the Windows NT operating system. In each room, touch-sensitive pads control lighting, music, and climate. Visitors will wear small electronic pins, which will let the computers know who and where they are. Lights and other settings will adjust automatically. Floors throughout the house (and the driveway) are heated."

• Much of the home is nestled into the hillside and underground. According to the architects: "A sod-covered guesthouse is sited at the highest point of the property. Invisible on approach and entered between two concrete walls, the building is choreographed to give a sense of moving through the earth to discover the distant lake and mountains."

But our favorite discovery of all when researching this post? You can own Bill Gates' home too!Just download the paper toy version at PaperToys.com.

A virtual tour of the home: