EDITOR'S NOTE: SPACE.com has learned that the auction has been extended until Sept. 10 at 6:00 p.m. ET.
Three bidders will have the chance to join filmmaker James Cameron in a state of weightlessness aboard an upcoming plane flight, in an auction to fund high-tech competitions offered by the X Prize Foundation.
Cameron, famed director of "Avatar" and "Titanic," and his wife will be among the guests on an Oct. 9 flight from Los Angeles aboard G-Force One, a modified Boeing 727-200 jet flown in parabolic arcs across the sky to induce a few moments of zero gravity.
The plane's owner, Zero Gravity Corp. of Vienna, Va., will auction off three passenger spots on eBay beginning Tuesday, Aug. 31. The auction ends Sept. 10 at 6:00 p.m. ET.
"All proceeds from this eBay auction will go the X Prize Foundation to help design future prizes intended to drive radical breakthroughs for the benefit of humanity," said X Prize Foundation chief executive and chairman Peter Diamandis in a statement.
The X Prize Foundation is a nonprofit group based in California that offers prize money to stimulate technological breakthroughs.
In 2004 the foundation bestowed $10 million on the Scaled Composites company for building the first privately funded reusable manned spacecraft. Since then, the foundation has developed new contests with multimillion-dollar prizes for achievements in moon exploration, automotive fuel economy and genetics research, among others.
Cameron serves on the foundation's Exploration Advisory Committee.
"My wife Suzy and I are really excited about flying in the 727 for the Zero-G experience," Cameron said in a video about the upcoming flight. "I've done it before and it's really an amazing experience. So come along with us and we'll go get weightless! Bid high on this one because it's a great way to support our (the X Prize Foundation's) efforts in space."
The flight will take off from Van Nuys Airport in Los Angeles. Also on board will be FOC Films chief executive Jim Gianopulos and author Tim Ferriss ("The 4-Hour Workweek"), X Prize officials said.
NASA uses planes similar to G-Force One to train its astronauts. Parts of the movie "Apollo 13" were shot aboard such a plane, and a number of noted personalities, including Stephen Hawking, Martha Stewart and Ozzy Osbourne, have flown aboard Zero Gravity flights. One couple had a weightless wedding aboard the plane.
To bid on seats for the upcoming flight, visit http://eBay.com/cameron.