If you haven't lived in China for a while, you will never guess it. Prior to my stay in China, I thought the most famous foreigner would be someone like George W. Bush or Beckham. How wrong I was.
Dashan is what he is known as in China, Mark Rowswell is his real name. There is a detailed description of this guy on Wikipeidia
And he has a website, too
Basically, Dashan is a really average, plain-looking Canadian from Ottawa. To most people, he is really not that noticeable at all. The only talent he has is that he can speak really really good Chinese, even better than most of the Chinese people as the majority of the population has an accent of some sort depending on where they live. Dashan, on the other hand, speaks perfect Beijing Mandarin, the kind you will find spoken by the news anchors on CCTV. Well, I guess it is quite hard to master such a difficult language.
The Chinese people are very taken by this guy's ability to speak like one of their own. You will see this guy practically on every channel (well, maybe not the adult's one...) when you turn on your TV in China. He appears primarily on CCTV programs, teaching people Chinese/English, travel/culture shows...blah blah blah. He hosts New Year's special shows (the ones where foreigners will sing Chinese songs, do Chinese dance) and he has endorsed quite a number of products, especially things to do with learning English and stuff imported from Canada.
Gaikokujin tarento (foreigner talent) is the term they use to describe people like Dashan in Japan. Apparently the Japanese people also find foreigners who can speak fluent Japanese amusing. I guess this is one new alternative for those who want to get into the entertainment industry but don't have any real talent : go learn Chinese and be really good at it, then head East for the gold mine.