The Russian ruble fell to near the psychologically important level of 30 rubles per dollar on the MICEX currency exchange on Friday, its lowest level since the beginning of August.At 18:20 Moscow time the ruble was at 29.8 rubles per dollar and 41.2 rubles per euro. The central bank\'s official rate for the weekend is 29.7 rubles per dollar. The euro and the European stock exchanges plunged on Friday after chief economist of the European Central Bank Jurgen Stark said he would resign. The euro dropped to 1.37 dollar, the lowest since February, amid growing concerns for the euro zone\'s economic recovery.