MLK dissuaded Uhara from quitting Star Trek

Very cool.  I'm not a Trekie but I do like the show.  I am glad Nichols decided to stay.  
 
I believe it's called "trouble with Tribbles".  More of a tounge in cheek episode but I have always had to chuckle when I see it.  There was also an episode where there were two men, one half white half black and the other half black and half white.  It dealt with racism and hate.  I always remember that one.  Worth a watch as well.  
 
* Found it.  "Let That Be Your Last Battlefield" is the name of the episode.