Scooby-Doo
The first episode of "Scooby-Doo, Where Are You!" "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured veteran voice actor Don Messick as Scooby-Doo, radio DJ Casey Kasem (later host of radio's syndicated "American Top 40") as Shaggy, actor Frank Welker (later a veteran voice actor in his own right) as Fred, actress Nicole Jaffe as Velma, and musician Indira Stefanianna Christopherson as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from "The Jetsons" (1962–63), also voiced by Messick. Seventeen episodes of "Scooby-Doo Where are You!" were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks.
The Addams Family
The Addams Family's first animated appearance was on the third episode of Hanna-Barbera's "The New Scooby-Doo Movies", "Scooby-Doo Meets the Addams Family" (a.k.a. "Wednesday is Missing"), which first aired on CBS Saturday morning, September 23, 1972. Four of the original cast (John Astin, Carolyn Jones, Jackie Coogan, and Ted Cassidy) returned for the special, which involved the Addamses in a mystery with the Scooby-Doo gang. The Addams Family characters were drawn to the specifications of the original Charles Addams cartoons. After the episode aired, fans wanted more animated adventures featuring the Addamses, and Hanna-Barbera obliged.