Bill Gates, Warren Buffett : Give away half your money!

This is one of those things where nothing that I might say will make it anymore believable.  Heck, even the quote from The Wall Street Journal seems like a hoax:

Bill Gates and Warren Buffett announced today that 40 signers, including at least 30 billionaires and other wealthy families, had officially made the Giving Pledge–a promise to give away more than half their fortunes.

I think they are just trying to prove Chris Rock wrong (from 1:28 and further):