Happy 47th Star Trek!
It was on September 8th 1966 that Star Trek debuted on NBC in the U.S.A. The episode chosen to be broadcast first was actually the fifth produced – “The Man Trap“. Also, as commenters have pointed out, happy 40th anniversary to Star Trek: The Animated Series, serendipitously, it too debuted on September 8th in 1973 So fire up Netflix, Amazon Instant, Hulu Plus, Star Trek.com, or your DVD or Blu-ray copy of TOS and celebrate!