"One of the worst ways to stop someone from telling sexist jokes is to tell him the joke isn’t funny. He’ll assume that you’re humorless and that he needs to save the good stuff for the right audience. If you really want someone to stop telling sexist jokes, you need to tell him, ‘I don’t get it’ and then step back as he tries not to say, ‘It’s funny because women are stupid.’"
http://gaircyrch.tumblr.com/ (via earlyfrost)
This is also true of racism or any ism, really. A good friend taught me this years ago. When someone tells a racist (or any other fucked up) “joke”, just play stupid, like you really don’t get it. That way they have to explain to you, in detail, that POC are somehow clownable, inferior, etc. They actually have to reveal themselves as racist.