The Golden Girls (1985)

Defying the TV-industry "rules" that A) no viewer is interested in watching a situation comedy with an all-female cast and B) no viewer wants to see anybody over the age of 34, The Golden Girls was one of the few sitcoms in which all of the regulars were women, and none was under the age of 50 -- and it turned out be NBC's biggest hit of the 1985-1986 season.