A Jewish family were sitting down to a family dinner, and the son asks his father if he can borrow $50. The father responds, $40? Why do you need $30?
My informant first heard this joke a few months ago at a bar with his friends. He now shares the joke in similar friendly, jovial atmospheres. He told it to a group of our friends one night when we went out to dinner and after someone made a comment about him being Jewish. His joke, in response to the comment, sparked an exchange of jokes among the group.
My informant tells the joke because he feels that it strikes a balance between exaggerating a stereotype, that Jewish people are stingy, and being overtly offensive. Since he identifies as Jewish, he never feels uncomfortable saying the joke, but only says it when surrounded by people whom he thinks will not be offended.
Another reason that the joke may not be seen as offensive is that the joke is somewhat complimentary of the Jewish father. The joke implies that the Jewish father is intelligent enough to trick his son into believing that he originally asked for $30. This joke plays on two Jewish stereotypes: stinginess and craftiness. The joke retains its humor despite generalizing about a group of people because neither of these stereotypes is exceptionally insulting, but Jewish and non-Jewish people alike acknowledge the stereotypes.