It's About Time (1966-67) was about two astronauts who, after breaking the speed of light, accidentally travel back in time to prehistoric Earth. Unable to return, they make friends with the "natives" in the stone age. An attempt to do a live-action version of The Flintstones.
Halfway through the season, having run out of stone-age jokes, the show was retooled by having the astronauts manage to fix their spacecraft and return, bringing some of the stone-age characters with them, turning the show into a Fish out of Water about stone-age characters trying to figure out modern life. This wasn't very successful either, and the show only lasted the one season.
- 1 Million B.C.: The astronauts accidentally break the time barrier and get stranded in One Million B.C.
- A Lesson Learned Too Well: In "To Sign or Not to Sign", Captain Mackenzie and Lieutenant Canfield teach Gronk and Shad how to sign their names. The two end up signing up for a large variety of goods and services sold by door-to-door salespeople.
- Animated Credits Opening: Revamped with its plot points reversed after the Retool.
- Blazing Inferno Hellfire Sauce: In "Stone Age Diplomats", the food that Shad and Gronk prepare for the astronauts and the "Ambassador of Nordania". It's a mixture of everything with a generous helping of hot sauces mixed in. Naturally, the astronauts, the ambassador and the landlord choke or gulp down water. Shad and Gronk love it.
- Comic-Book Adaptation: One issue long.
- Contemporary Caveman: After Shad, Gronk, Breer and Mlor return to the 20th century with Mac and Hec.
- Decided by One Vote: In the episode "Mark Your Ballots", Mac and Hector convince the cave-people to have an election, running Boss against Gronk. The election results in a tie, but at the last minute an old woman named Trong, who lives near the tar-pits, arrives to vote for Boss.
- Everytown, America: Riverview, Ohio; Lt. Hector Canfield's oft-mentioned hometown.
- Expository Theme Tune: It's About Time, It's About Flight, It's About Travelling Faster Than The Speed of Light. In an interview, Sherwood Schwartz said it was the best theme tune he ever wrote. That's something, considering he was responsible for the iconic and well-loved The Brady Bunch and Gilligan's Island theme tunes.
- Fantastic Comedy: Time travel, astronauts, cave-people, dinosaurs.
- Fish out of Temporal Water: The astronauts in One Million B.C., particularly Hector who never seems to try to adapt or adjust his behavior to the circumstances. Later, Shad, Gronk, Breer and Mlor in the 20th century. It's implied, though, that they'll slowly get better.
- Fish out of Water: Again, the astronauts in One Million B.C., and the cave-family in the 20th century.
- Getting Crap Past the Radar: In the pilot the female Cave Dweller was named Shag. The radar then got fixed for the series in which her name became Shad.
- Kissing the Ground: In "Twentieth Century Here We Come", upon landing back in the twentieth century, Hector remarks to Mac that they ought to kiss the ground, the astronauts being grateful for being back in their own time. Unfortunately, Literal-Minded cave-people Gronk, Shad, Mlor and Breer believe this is actually a ceremony one practices on the astronaut's "side of the hill." They kiss the ground.Shad: Strange custom.
- Machine Worship: In "School Days, School Days", Shad and Gronk make a sacrifice to the garbage disposal calling it the "god of Garbage"! At the end of the episode, after Mac and Hector enroll them in night school to catch up on a million years of civilization, Gronk mentions they're going to be taught about Edison, god of the Electric light.
- Man-Eating Plant: In "Androcles and Clon", the astronauts are attacked by a man-eating plant in the jungle. The plant attacks them with its vines and tries to pull them into a thicket. Mac and Hector are able to free themselves with a little difficulty.
- My Life Flashed Before My Eyes: In "Androcles and Clon", it was said by both astronauts after a narrow escape with being clubbed and pushed off a cliff by Clon.
- Nubile Savage: Cavegirl Mlor, the daughter of Shad and Gronk. She's a beautiful teenaged blonde, dressed in animal furs. This is in spite of living in a cave in One Million B.C., amongst a very primitive tribe. Astronauts Mac and Hec were both instantly smitten when they first met her in "And Then I Said Happy Birthday To You".
- Slapstick Knows No Gender: Shad. Shad tended to suffer from more slapstick misfortune once she returned with the astronauts to the present, especially in the episode "To Sign or Not to Sign" where she joins a gym.
- There's No Place Like Home: The astronauts, having been stranded in 1 Million B.C., fix the Scorpio E-X-1 and get back to the future midway through the series ("Twentieth Century Here We Come"). However, they take their friends Shad, Gronk, Mlor and Breer with them, and Hilarity Ensues as the cave family reacts to modern life.
- Time Travel: A round trip for the astronauts, one way for Gronk, Shad, Mlor and Breer.
- Trapped in the Past, turning into Get Back to the Future when they fix their spacecraft.