While he may not buy predictions for the end of the world on Friday, the man known for grandiose parties is planning his most elaborate soiree ever - just in case.

Two years in the planning, the party will take guests through games, challenges and performances by hedonists, evangelists, UFO watchers and transcendentalists, all set up in camps along mythical ley lines, or earthly energy fields, which they say crisscross the Garriott de Cayeux property in Austin.

Guests will be asked to think throughout the evening about what they would have done differently in their lives if the world did actually end, and whether, if they got a do-over, they could commit to living a passionate life without regret.

Near midnight, guests plan to witness the end of the world against the breathtaking backdrop of a two-story Mayan temple built on the banks of Lake Austin.

Proceeds from the $1,000 per ticket event will go to the X Prize Foundation, an educational nonprofit that encourages exploration, technological breakthroughs and other advancements through competition. The 144-seat event was nearly sold out on Thursday.

"I'm pretty sure the world will end with the expansion of the sun, which will envelope all the inner planets," said Garriott de Cayeux, 51, who wore a Mayan headdress at a dress rehearsal on Wednesday night. "But I think we have a little while yet."

In the Maya Long Calendar, December 21 marks the end of the 13th bak'tun, an epoch lasting roughly 400 years. U.S. academic Michael Coe said in 1966 the event might signify a Mesoamerican Armageddon, leading to the phenomenon of 2012.

Coe has told friends and colleagues he never meant to forecast an apocalypse, and modern Maya have been baffled by the hype exemplified by the party in Austin.

Some 120 volunteers form part of the production planned by Garriott de Cayeux and his friend Brad Henderson, a magician, hypnotist and mentalist in Austin.

At the Salvationist Sideshow and Carnival of Curiosity, guests will watch water turn to wine as a performer known as The Enigma, tattooed from head to toe, bears witness to his salvation.

In the Here and Now tent, guests will sit on plush pillows and play boundary-pushing games. Nearby, the transcendentalists will challenge guests to walk on hot coals.

"If they're willing to come along for the ride, I guarantee you when the clock strikes midnight, they will never be the same again," Henderson said.

Garriott de Cayeux developed the video game Ultima beginning in the 1980s, and he became even more widely known when he paid tens of millions of dollars to visit the International Space Station as a private tourist in 2008.

He is known for imaginative parties, including a Titanic party on a barge in the middle of the lake. It sank, forcing surprised guests to don life jackets and swim ashore.

"We're used to doing these not only big things," he said, "but ones that kind of push people's buttons, push their comfort zones, a little bit." (Editing by Corrie MacLaggan and Steve Orlofsky)

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