When Stalin was told that Radek was telling jokes about him, he asked him to come in for a discussion. Radek enters and says, "Oh my God, what an apartment you have, comrade Stalin!" Stalin replies, "Soon, every Soviet person will live in such an apartment." Radek answers, "Let's make a deal, comrade Stalin: either I'm the one telling jokes, or you are."
Karl Radek was a Soviet revolutionary, friend of Lenin, backer of Trotsky. He is remembered for his wit; Radek was notoriously quick on his feet, ready with a retort, a joke, a comeback. But no, the joke above was not made up by him.
Radek's joke-telling became so legendary that he himself often became the subject. Even during his life, Radek became a mythical figure, the symbol of anti-establishment, the opposition to Stalin, the clever Jew who always bested his supposed superior.
Mythical figures often have tragic endings, and so did Soviet revolutionaries. Radek died in a labor camp in 1939, two years after Stalin had him jailed. One of the accusations? Radek made up too many jokes...