Back in September, Wynn Resorts (NASDAQ:WYNN) CEO Steve Wynn was spending two hours each day on Chinese lessons. This is a man who, at the age of 65, is worth $3.4 billion.

Yet he's learning new tricks.

Why? Because the Wynn Macau -- Mr. Wynn's latest mega-casino -- was getting set to open just off the coast of China. That's right on the doorstep of some 3 billion potential customers.

Big bets for big paydays
And how has the Wynn Macau fared? Quite well -- though the stock has slid after the company announced it would slow expansion on Macau.

And why is Wynn slowing expansion? Because Steve Wynn isn't the only billionaire going gaga over foreign markets. Wynn rival and Las Vegas Sands (NYSE:LVS) CEO Sheldon Adelson, himself worth $26.5 billion, and $22 billion casino giant MGM Mirage (NYSE:MGM) are making similar investments in Macau's potential -- with expansive resorts to open later this year.

Entrepreneurs and investors alike
Then there are the master investors who have been buying up Chinese stocks at a rapid clip. Top investment firm Ruane Cunniff now has a nearly $10 million stake in TOM Online (NASDAQ:TOMO). Legg Mason's Bill Miller has stakes in a number of small Chinese concerns, including Sina (NASDAQ:SINA) and NetEase (NASDAQ:NTES).

Even Warren Buffett stoked the international frenzy in 2006, when he picked up 80% ownership of Israel's Iscar Metalworking.

The question we have to ask
So -- and you had to know I was coming around to this -- what have you been adding to your portfolio lately?

Me? I know I'm underexposed to international stocks, and I've resolved to make 2007 the year I do something about that. In fact, I recently returned from a research trip to China, India, and Macau with Motley Fool Global Gains advisor Bill Mann. You can read all of our research and recommendations from the trip by clicking here to join Global Gains free for 30 days.

This article was originally published on Jan. 19, 2007. It has been updated.

Tim Hanson owns shares of Wynn Resorts. Sina and TOM Online are Stock Advisor picks. NetEase is a Rule Breakers pick. Legg Mason is an Inside Value choice. No Fool is too cool for disclosure.