OK, I gotta admit -- when these guys play the Half Game, they play it for keeps. If you missed this Fortune story, Bill and Melinda Gates and Warren Buffett hosted a dinner for billionaires at which they asked each individual to give away half of their net worth to charity either in their lifetimes or after their death.

People have been e-mailing me all day. "Look what you started," one wrote. "Hmm, did Bill and Melinda Gates read your book?" another asked. I can't say whether they did or not, although Hannah and I did speak at Microsoft (he wasn't at the talk) and I know a friend put it in the hands of Bill Gates Sr.

But of course that doesn't matter; what does matter is that these three giants of philanthropy are challenging their peers to step up, to give generously and beyond. I can only hope and pray that the message is heard: Most of us have more than we need -- and we have the ability to improve the world when we give.

I do offer one caveat, though. I hope the incredible magnanimous effort by the Gateses and Mr. Buffett doesn't reinforce the impression that philanthropy is a game playable only by the uber-affluent. As our family always says, everyone has more than enough of something -- time, talent or treasure -- so everyone can be a giver (and in turn reap the joys of that giving).

So, let's take the inspiration from the biggest of the big guys (and gal) and go for it. Half it is!