During a dinner gala in Beijing, two top American billionaires Bill Gates and Warren Buffett have asked about 50 Chinese tycoons to give away some of their wealth for charity in red envelope (hong bao). As two of the world's richest people, both Gates and Buffett have donated billion of dollar of their fortunes for charity works. Citing Gates, reuters.com reported that Chinese super-rich saw their efforts were at an early stage and have asked American billionaire for advices.