Following a series of private meetings with Warren Buffett and Bill & Melinda Gates over the past year, 40 American billionaires and multi, multi-millionaires have signed a pledge to give away at leaset 50% of their net worth.

The list includes people like Star Wars creator George Lucas, Mayor Bloomberg, Larry Ellison, and T. Boone Pickens.  Gates and Buffett are reportedly meeting with billionaires in India and China to get them to agree to do the same, hoping to set an example like Rockefeller and Carnegie that wealth created in the free market system should go back for the good of society.  Lucas, for example, plans on using his massive fortune to further education because "the human race depends upon" it.