In the pilot, And Then I Wrote Happy Birthday to You (1966), Imogene Coca's character was called "Shagg". When the producers were made aware of the fact that "shag" is a slang term for sexual intercourse in the U.K., they changed her name to "Shadd", but didn't amend the pilot, which aired (as the premiere episode) as originally filmed.
Halfway through the one-season run, the plot was reversed in a desperate attempt to bolster the show's low ratings. The two astronauts, who had traveled back in time, found a way to return to 1966 and took the stone-age family with them; so the rest of the run played out with Gronk, Shadd, et al. trying to adjust to NYC life in 1966.
This show used many of the props that were used on Gilligan's Island (1964), Sherwood Schwartz's other show, which also aired during the 1966-67 season.
Although the show lasted only a single season and was not ranked highly in the Nielsen ratings, it was immortalized when Isaac Asimov referred to it in an essay he wrote in February 1967 titled, "Impossible, That's All" (about how it was impossible for anything to go faster than light). The essay was later included as a chapter of Asimov's book, "Science, Numbers and I".
Sherwood Schwartz believed that the show was a few years ahead of its time and had the show been on around the time of the first moon landing in 1969, it could have been a hit.