An old "visit to the library" joke, as re-told by Slovenian film critic, Slavoj Zizek, in one of his recent books:

Marx, Engels, and Lenin are asked whether they would prefer to have a wife or a mistress. As expected, Marx, rather conservative in private matters, answers, “A wife!” while Engels, more of a bon vivant, opts for a mistress. To everyone’s surprise, Lenin says, “I’d like to have both!” Why? Is there a hidden stripe of decadent jouisser behind the austere revolutionary image? No-he explains: “So that I can tell my wife that I am going to my mistress, and my mistress that I have to be with my wife …” “And then, what do you do?” “I go to the library to learn, learn, and learn!”