How do I deal with a co-worker that makes remarks based on a person's culture or race?

To be more specific, they comment that the boss is passionate about work and micro manages because he is Iranian. Or she got a bonus and was surprised because the people who gave the bonus were Jewish. It is driving me nuts and it is just rude. Or you know that so and so is whatever nationality. I'm very frustrated and it isn't like I can go to the boss. I thought that stuff was against the law.