Did you know there were only 24 episodes of the Jestons? The first season just came out and it was the only one. Very interesting. It was also written for prime-time, but stuck around on Saturday morning for years to come. Came out the same time as the Flintstones, which had the longest animated run before the Simpsons.
An interesting discussion in the editorial review of the Flintsones on Amazon comparing the Flintsones and the Simpsons.