(via https://www.youtube.com/watch?v=EP4XRBsfuAs)
In the era before for-profit media fandom conventions, Star Trek fans organized their own events and, in one case, even produced their own TV ad. This is for the 1975 Equicon, a convention held in Southern California. (links go to Fanlore, the fan run wiki about media fandom).
“The
members of S.T.A.R. San Diego ran Equicon 75 at the El Cortez Hotel,
with most of the STAR TREK cast attending as guests. The “Captain” in
the ad is now-famous science fiction author Greg Bear. (We knew him
when!) Yes, it’s blurry. (Sorry.) It’s been pieced back together from a
34-year-old silent 8mm film, converted to vhs, then to dvd (with the
sound dubbed back in from an ancient cassette tape), then converted
again to an mp4 file! “