Who first obtained a copy of Krushchev's secret speech to the 20th Party Congress of the CPSU in 1956 and spread the news to the West? On this occasion it seems it really was the Jews. There's a long and interesting piece about it here - 'the greatest intelligence-gathering achievement for the Israeli intelligence community'. (Thanks: L.)
Update at 6.00 PM: See also here. (Thanks: DS.)