The Enterprise finds the S.S. Botany Bay, a 1990's sleeper ship carrying a group of genetically bred supermen led by Khan Noonian Singh.
Air Date: 02/16/67
Director: Marc Daniels
Up there with "Arena" as far as classic Trek episodes go, "Space Seed" is even more infamous in that it gives us the backstory for one of the greatest sci-fi movies of all time. I admit I had never seen this episode when I watched Wrath of Khan in theaters in 82. The terrific thing is you don't need to see it to enjoy that film. One fun bit of trivia. When Kirk smashes the glass on Khan's sleeping chamber, his phaser falls off his hip. You can see Deforest Kelley look at the phaser and then up in the direction of the camera as if questioning if they were going to call a cut for a retake.