Keith Partridge was a drug addled teen. In one episode of this show, I mean.
Grandma Walton helped herself to a vacationing neighbor's living room furniture.
Clarice Starling and her best friend got themselves stuck on the roof of their elementary school.
Eddie Munster was the head of a gang of child burglars (he only did it because Mother told him to).
Roy DiLucca saved someone from a warehouse fire after he started it while robbing the place.
The Other Darrin: Jean Reed was played by two different actresses, and her incarnation in season seven is practically Same Character, But Different. The decade can account for her radically different wardrobe and hairstyle choices, but also gone is the understanding Jean Reed who knew the risks and was happy anyway, until in the final episodes she almost seems to resent her husband's job.
You Look Familiar: Gary Crosby was a part-time regular as Officer Ed Wells on Adam-12 and appeared in two different roles (the first time as a firefighter, the second time as a publicity-happy paramedic) in season one of Emergency!.