As Microsoft's somber Bill Gates expands his $29 billion foundation for global health and education, the company's more exuberant co-founder has been spending his own fortune -- now about $16 billion -- like a kid in a candy store.
In the family of Microsoft, Paul Gardner Allen is the quirky twin of his boyhood friend William Henry Gates III, whose $53 billion net worth and public persona tower over Allen's.
Both Seattle boys dropped out of college to create the software giant Microsoft, but Allen, a private man with flamboyant interests, left the company in 1983 when he was diagnosed with cancer that was later cured.
Allen is the sixth-richest man in the world and owns an array of toys that would make any brother jealous. His 416-foot yacht "Octopus, with its permanent crew of 60, two helicopters, a submarine and a remote-controlled vehicle for crawling the ocean floor, cost him $200 million in 2003.
Though Allen supports scientific causes, he also owns two professional sports teams and a pop culture museum devoted to rock and roll and science fiction -- a flashier face of Microsoft than Gates' battle against AIDS in Africa.
Allen's philanthropy reflects a growing trend among the rich of speading the wealth around to multiple charities and doing it before they die. But critics say that given his wealth, Allen should be more generous.
In 2006 Allen donated a modest $50 million -- about 5 percent of his total wealth, according to the Chronicle of Philanthropy. In contrast, the Bill and Melinda Gates Foundation spent about 35 percent of their net worth on charitable causes.
Peter Singer, professor of bioethics at Princeton University, said the "super rich" should spend less on extravagant lifestyles and put their money "to work to make the world a better place.
"Gates has made a very significant commitment to reducing human suffering, and we should applaud him for that, even if he still has far more money and a much more lavish home than anyone can possibly need," said Singer.
"But Allen falls below any standard for a minimally decent level of philanthropy," Singer continued.. "And look at the things he spends his money on -- sports teams that are losing tens of millions of dollars a year, and a yacht that is the fourth-longest in the world. Really, is that what the world most needs right now?"
Still, Allen's largesse makes the Chronicle's list of "America's Most Generous Donors," which will be published this month." He falls somewhere around 40," said the Chronicle's editor, Stacy Palmer.
"He combines old philanthropy with a new style," said Palmer. "With Bill Gates you don't get a sense of what motivates him as a person. Paul Allen is somebody who shows his passions through his giving. But he's very private about it and not self-aggrandizing."
Allen was not available for an interview because he was on a pleasure trip, but he told the Oregonian in February that he was motivated to give to scientific research because of his own experience with cancer.
"You look at what Paul has done since Microsoft -- specifically in the Northwest -- and his actions speak for themselves," said Michael Nank, spokesman for Vulcan Inc., which oversees Allen's various business and charitable ventures.