Richard Garriott is watching comets from the observatory atop Britannia Manor, his home in Austin, when he sees a shadowy figure scale the security fence and cross the lawn. The gargoyles with the glowing eyes on the roof don’t deter the intruder; neither does the working cannon at the front door. Then the prowler hurls a large stone through a glass door leading to an indoor grotto, the one with hot-and-cold-running rain showers. Although the foyer under the observatory stairs is filled with crossbows, battle axes, armor, and swords, Garriott reaches for his Uzi. (“It’s the only weapon I know how to load,” he explains later.) The intruder is climbing the stairs, ignoring warnings to stop, so Garriott fires a warning round above the intruder’s head. The bullet blows a hole clean through the house.

If this sounds like life imitating a video game, well, that would be appropriate. Garriott is one of the world’s premier game designers, and the unwelcome visitor–who undressed and climbed into bed in a guest room, where the police arrested him–is a deranged fan of Garriott’s alter ego, Lord British, the ruler of the virtual realms of the Ultima game series.

It has been 10 years since Garriott, now 46, and his then-publisher, Electronic Arts , released Ultima Online and popularized the genre of massively multiplayer online role-playing games. Today, millions of people worldwide spend $1.9 billion a year–much of it in yen, or renminbi, or euros–to play Ultima or its newer rivals, including World of Warcraft, Lineage, Eve Online, and EverQuest.

Garriott himself has become a legend, and not just to his rabid fans. He visited the Titanic aboard a Russian mini submarine as an investor in a company that sells deep-sea tourism. He accompanied British astrophysicist Stephen Hawking on a ride on the “Vomit Comet,” a modified Boeing 727 that soars and dives in parabolic arcs to create a simulation of the weightlessness of space. He is an investor in that business, Zero Gravity Corp.

He is also a board member of Space Adventures Ltd., which is hawking $20 million tickets for a short stay on the International Space Station, via a Russian rocket. (Former Microsoft executive Charles Simonyi was the most recent client.) Garriott himself has taken cosmonaut training at Russia’s Star City and hopes to follow his father, former NASA astronaut Owen Garriott, and become the world’s first second-generation space traveler. He even bought at auction a derelict Russian Luna rover that is now parked on the moon, making him, he says, “the world’s only private owner of an object on a foreign celestial body.”

Garriott has just released his first new video game in years, and online gamers have been buzzing with anticipation. The game, called Tabula Rasa, has been in the making since 2001–an inordinate length of time, particularly for someone whose first game design, as a 17-year-old, took just six weeks (and hauled in more than $150,000). Garriott and his older brother, Robert, now CEO of NCsoft North America, cofounded their first company in their parents’ garage. “Richard’s the creative guy, and I’m the business guy,” says Robert, who holds an MBA from MIT’s Sloan School of Management. They sold their company to Electronic Arts in 1993, then broke away in 2001 to hook up with NCsoft, the South Korean maker of the wildly successful (in Asia) Lineage online-game franchise.

The launch of Tabula Rasa “is very significant in the game community, primarily because of Richard’s involvement,” says Stephen Butts, executive editor of IGN PC, an online network devoted to video games. “Richard Garriott is finally coming back. He’s got quite a legacy.”