Airing from September 1966 to June 1969, Star Trek was treated like a bastard step-child at NBC.  The time-slot kept changing, and promotion dwindled.  It was only after cancelation in 1969, and the lobby for syndication, that Star Trek became the juggernaut we all know today.
With 79 Episodes + The original Pilot, the series has been the influence for numerous technologies invented throughout the 1970's and 80's, including; the home computer, the personal computer, medical scanning, cellular telephones, and tasers.