I don't recall seeing this posted previously, and my apologies if it's been discussed before, but I was poking around YouTube and I found a clip of an episode of Gene Roddenberry's single season show The Lieutenant,
which is notable because it features Nichelle Nichols in one of her earliest TV roles (it's apparently not her first, as some have claimed), Don Marshall of Land of the Giants,
and Dennis Hopper! You only see series star Gary Lockwood for a few moments in the video, but, hey, check out the groovy music for a Marine. Swingin!
Click to see a clip from The Lieutenant episode "To Set It Right" (1964)