William Hanna wanted to do a family-style series, but he and Joseph Barbera couldn't agree on the setting or the costuming. Suddenly, Hanna exclaimed, "Let's do it in a caveman setting! They won't wear clothes, they'll just wear animal skins!" After that great idea everything from then on "perfectly fell into its place."
The imminent birth of Pebbles was a major worldwide sensation. TV networks around the world held viewer contests to pick names, weights, sexes, and other aspects of the birth. The night that Wilma told Fred she was pregnant (January 25, 1963), the end of the show featured a voiceover where a narrator said, "That's right, folks, the Flintstones ARE going to have a baby, and you can win a trip around the world!" The contest was to pick Pebbles' birth weight, and the winner, a Florida butcher, did receive a round the world trip plus $2,000 spending cash. William Hanna & Joseph Barbera appeared live on the March 8 show to announce the winner (Pebbles was born on the February 22 show.) Of course, this voiceover has been removed from subsequent airings since that night.
To capitalize on the then-current craze of "ghoul comedies," such as The Addams Family (1964) and The Munsters (1964), the Gruesomes (Weirdly, his wife Creepella and their son Gobby) were introduced in the fifth season as the Flintstones' newest neighbors. But they appeared just twice. They were in The Gruesomes (1964) and The Hatrocks and the Gruesomes (1965).
The Flintstones had three addresses during the series' six seasons run: 222 Rocky Way, 345 Stonecave Road, and then 301 Cobblestone Way. The final ("official") address given was 301 Cobblestone Way, Bedrock 70777. (70777 is the real ZIP code for Slaughter, Louisiana.)
For almost all of season two, after Mel Blanc's near-fatal automobile accident on Tuesday, January 24th, 1961, the show was taped in his bedroom where he lay in a full-body cast. Daws Butler, who had voiced both Fred and Barney in the original pilot The Flagstones (1960), filled in as the voice of Barney Rubble for five episodes. The titles and address links (where Daws Butler filled in for the recovering Mel Blanc are: 1st The Hit Song Writers (1961), 2nd Droop Along Flintstone (1961), 3rd Fred Flintstone Woos Again (1961), 4th The Rock Quarry Story (1961), and 5th The Little White Lie (1961). Producer Joseph Barbera did say that as many as 16 people, along with recording equipment, speakers, and other items crowded into Mel Blanc's bedroom as he was recovering.