Back at the beginning of the year, 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 $3.9 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. Despite the stock's recent slide, analysts see it tracking above previous estimates and contributing some $300 million in EBITDA in 2007.

But 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 $28 billion, and $24 billion casino giant MGM Mirage (NYSE:MGM) are making similar investments in Macau's potential -- with their own expansive resorts.

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 has been adding to its stake in SINA (NASDAQ:SINA), and Legg Mason's Bill Miller -- another SINA owner -- has another 6.8 million shares of China's 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?

Even if you didn't make foreign stocks a part of your portfolio in 2007, it's not too late. While China's markets look a bit frothy, the valuations in other emerging markets look downright appealing. In fact, I recently returned from a research trip to Latin America 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 is a Stock Advisor pick, and NetEase is a Rule Breakers pick. Legg Mason is an Inside Value choice. No Fool is too cool for disclosure.