Many currency pairs will move about 50 to 100 pips (sometimes more or less depending on overall market conditions) a day. A pip (an acronym for Point in Percentage) is the name used to indicate the fourth decimal place in a currency pair, or the second decimal place when JPY is in the pair. When the price of the EUR/USD moves from 1.3600 to 1.3650, that's a 50 pip move; if you bought the pair at 1.3600 and sold it at 1.3650 you'd make a 50-pip profit.
One unique aspect of this international market is that there is no central marketplace for foreign exchange. Rather, currency trading is conducted electronically over-the-counter (OTC), which means that all transactions occur via computer networks between traders around the world, rather than on one centralized exchange. The market is open 24 hours a day, five and a half days a week, and currencies are traded worldwide in the major financial centers of London, New York, Tokyo, Zurich, Frankfurt, Hong Kong, Singapore, Paris and Sydney - across almost every time zone. This means that when the trading day in the U.S. ends, the forex market begins anew in Tokyo and Hong Kong. As such, the forex market can be extremely active any time of the day, with price quotes changing constantly.