There are various ways investors and traders play the dollar's rise and decline. One such way is by purchasing or selling options on foreign currencies. For example, if you think the dollar is headed down against the yen, you will want to load up on currency options that will let you buy yen for less when its taken off against the dollar. Another way to play the dollar is to invest in the stocks of foreign companies. If the dollar's headed down, you will protect the value of your money by investing abroad. And when the dollar reverses course, you can sell out your foreign holdings and bring your money back to the states.