6. Mac And Hector - It's About Time (1966-1967)
Sherwood Schwartz, flush with success from his hit show Gilligan's Island, came up with the idea for a series about two astronauts who are thrown backward in time and must live among the dinosaurs and cavemen. The two astronauts, named Mac and Hector, live with a cave family in prehistoric times. After 18 episodes, and plunging ratings, the show was modified to have the astronauts repair their ship and travel forward in time, bringing the family of cave dwellers with them. This show wasn't very good, but for a few weeks in 1966 it was a popular series. It might have been even more popular in the UK had the cave woman's name remained the same after the pilot episode. Originally called 'Shag', Schwartz changed the name to 'Shad' after being informed of the slang meaning of the word 'shag'.