I was reading this awesome discussion and a comment there brought a couple of my favorites to mind, both from advertising.
The American chicken producer Perdue had a well-known ad campaign featuring the president and CEO of the company, and the slogan "It takes a tough man to make a tender chicken." When they expanded into the Mexican market, unfortunately they didn't do quite enough research before putting up billboards there: the slogan translated into Spanish as "It takes an aroused man to make a chicken affectionate"!
How about you? Who else knows of any "lost in translation" mishaps?
Swedish vacuum cleaner maker Electrolux fortunately realized their slogan, "Nothing sucks like an Electolux", wouldn't go over well in the US. They did use it, however, in the UK and Australia. (