3rd Rock from the Sun - Season 5 Episode 6
Dick, Who's Coming to Dinner?

Dick is confused when Nina wont let him accompany her to her Black Student Union meeting, believing it to be a Weight Watchers type club; so, in an attempt to understand the concept, he mistakenly takes the Solomons to a racist white power rally. Dick realizes that the rally was a bad idea, and tries to make it up to Nina by firing her, to release her from what he calls her servile role (as he and Marys assistant), but she informs him that she is happy in her job. Meanwhile, Sally, Harry and Tommy are preparing to take part in a poetry competition and decide to use racism as their subject.