While Star Trek is often dismissed as a weird subsection of nerd culture, it's hard to downplay how hugely important it was to society (outside of the convention world) - the series, the brainchild of creator Gene Roddenberry, presented a vision of the future that was almost unheard of at the time (near the height of the Cold War): it was a future that was bright, where the possibilities were endless. It was a future where people of all beliefs, nationalities, creeds, races, and species worked together to achieve great things. It was a future of tolerance and peace. While the rest of the world was expecting the future to be one of burnt skies and atomic fallout, Star Trek said we'd be traveling through space (granted - to 1920's gangster planets and also wrestling with lizard people, but still).
Also, it contained the first scripted interracial on-screen kiss in television history, between Nichelle Nichols' Lieutenant Uhura and William Shatner's Captain Kirk (granted - while both were being controlled by faux-Greek aliens using telekinesis, but still).
Fun Fact: Executives at NBC demanded that they shoot two options for the scene - one where the two kissed, and one where they did not - out of fear that an inter-racial kiss would upset certain viewers. Both Nichols and Shatner purposely screwed up all of the takes of them not kissing - flubbing lines, acting erratic, and (in Shatner's case) even crossing his eyes to make the shots unusable and force the network to air the kiss.
But it almost didn't go this way - Nichols was about to leave prior to the show's second season to pursue musical theatre, when the reverend Martin Luther King Jr. asked her to stay on the show, since it was important for society to see a black woman working alongside a multi-ethnic group as an equal (also, he was a big fan of her and the show).
She relayed this story - and more - in an interview with prominent astrophysicist and all-around cool internet dude, Neil deGrasse Tyson: