Mantega is responsible for the all-important task of keeping the Brazilian growth miracle going by taming the double-threats of currency appreciation and inflation.

FORBES: Names You Need To Know: Guido Mantega

Last week, the central bank said it would double the supply of the currency in the market.

BBC: Bank of Japan begins stimulus sending Yen lower

While the fall of the greenback has aided manufacturing, a free fall of the American currency is a double-edged sword.

FORBES: Uncertainty Weighs On Manufacturing Jobs

You can also play the cratering yen via the YCS, which moves double in the opposite direction of the Japanese currency relative to the U.S. dollar.

FORBES: Japan Gets A Jolt As Kuroda Goes With Q.E. That Would Make Ben Bernanke Blush

Local currency government bonds have traded recently below 10%, where double digit yield is much more common.

FORBES: Brazil Government Debt Gets S&P Upgrade

But if prices double every week, you hit a point where people start to flee the currency altogether.

ECONOMIST: Zimbabwe's election

When Argentina's government defaulted and its currency was devalued against the dollar in 2001-02, foreign banks' assets took a double hit.

ECONOMIST: European banks