3rd Rock from the Sun - Season 5 - Eps 6: Dick, Who's Coming to Dinner?
Dick is confused when Nina won't 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 Mary's 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.
About 3rd Rock from the Sun

Title: 3rd Rock from the Sun
First Air Date: 1996-01-09
Last Air Date: 2001-05-22
Status: Ended
Rating: 7.5/10 (from 503 votes)
Language: EN
Seasons: 6
Total Episodes: 139
Network: NBC
Genres: Family, Sci-Fi & Fantasy, Comedy, Drama
Production Companies: Carsey-Werner Company
Synopsis
The high commander of an alien expedition lands on Earth -- what he considers to be the least-important planet -- in human form as Dick Solomon. Along for the ride are his alien compatriots Harry, Sally and Tommy -- who is the eldest of the group but is now angrily trapped in a teen's body.
Cast

John Lithgow
Dick Solomon

Kristen Johnston
Sally Solomon

Jane Curtin
Mary Albright

Joseph Gordon-Levitt
Tommy Solomon

Elmarie Wendel
Mamie Dubcek

French Stewart
Harry Solomon

Simbi Khali
Nina Campbell

Wayne Knight
Don Orville