What do Oprah, Bill Gates, Warren Buffett, George Soros and New York Mayor Michael Bloomberg have in common? It's a secret, but I am sure you can guess.

Money.

These and a handful of other mega-moguls coordinated their busy schedules to gather for a top-secret meeting in the Big Apple to talk greenbacks — not protecting them, but spending them, according to IrishCentral.com.

It was all for a good cause, but details of the mysterious May 5 meeting are vague. What is known is that each billionaire got to speak for approximately 15 minutes on the global economic crisis and how best to support philanthropic causes, IrishCentral reports.

Others in attendance also included David Rockefeller Jr., chairman of Rockefeller Financial Services; Ted Turner, founder of CNN; and John Morgridge, former CEO of Cisco, and his wife.

Gates wowed the crowd with his speech, Turner talked a lot, while Winfrey was said to be in a “listening mode," according to the IrishCentral.

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