Top 5 Most Intriguing Billionaires Taking 'The Giving Pledge'

(Aug. 4) -- Talk about leading by example. When Bill Gates and Warren Buffett unveiled the "The Giving Pledge" six weeks ago, it seemed like they were going out on a limb in agreeing to give the majority of their fortunes (from Microsoft and Berkshire Hathaway, respectively) to charitable endeavors. Now, after working the phones, they've convinced another 40 of their fellow billionaires to join the club.

A list of the new donors to the mass philanthropic project was released to the public today. It includes a variety of familiar names -- bigwigs in business, politics and entertainment. Eventually, Gates and Buffett hope that the list will be 10 times as long as it is now, with 400 total donors from around the U.S., Agence France-Presse reports. While the current list is worth a look on its own, Surge Desk elected to highlight our choice of the top five most interesting names to have pledges so far and their hauls (plus a few honorable mentions). Have a look below:

1. Michael Bloomberg: With a fortune of approximately $18 billion, New York City Mayor Bloomberg is considered by Forbes to be the eighth-richest person in the United States. While Buffett says that some of the potential donors he contacted cited the future of their children as justification to decline taking "the pledge," Bloomberg had a slightly different approach: "You don't want [your children] to look back and say, I was a member of the lucky sperm club," said Bloomberg.

2. Barron Hilton: That's right, Paris, your grandfather is donating at least half of the family fortune.The hotel heir, former Hilton Hotels co-chair and original owner of the San Diego Chargers is worth a cool $2.5 billion.

3. George Lucas: Not bad for an independent filmmaker. The "Star Wars" and "Indiana Jones" creator will be sharing the force of his $3 billion net worth.

4. Pierre Omidyar and Jeffrey Skoll: Never the ones to be outbid -- even when it comes to philanthropy -- the chairman and former president, respectively, of online auction hub eBay are worth approximately $9.5 billion combined.

5. T. Boone Pickens: Don't misunderstand Pickens when he says, "I like making money more, but giving it away is a close second." Over the years the Oklahoma-born financier has donated nearly $800 million of his riches.

Honorable Mention: Earning Surge Desk honorable mention from the pledge list are David Rockefeller (yes, heir to Standard Oil Rockefeller) and pizza-billionaire Thomas Monaghan, founder of Domino's Pizza.