Tuesday Weld played
Thalia Menninger, the unattainable girl of Dobie's dreams. She only dated
dreamboats, not regular guys like Dobie.
Zelda was played by Sheila James Kuehl, who went on to graduate Harvard Law School, teach law at Loyola, UCLA, and USC, and become the first openly gay person elected to the California Legislature. She is a respected politician, and in November of 2000, became the first lesbian member of California's Senate, taking about 70% of the vote in her race.
Chatsworth Osborne Jr. was played by Steven Franken, but that character did not appear in the first few episodes. The first spoiled rich kid was Milton Armitage, played by none other than Warren Beatty. Beatty has denied ever being in a TV series, but he's lying.
When Bob Denver got drafted, another future Bonnie and Clyde actor, Michael J. Pollard, was brought in to play the beatnik. He was not well-received in the role, and when Denver flunked the army physical, Maynard was quickly reinstated.