Entry in progress—B.P.
   
Wikipedia: Rat Pack
The Rat Pack was a group of actors originally centered on Humphrey Bogart. In the mid-1960s it was the name used by the press and the general public to refer to a later variation of the group, after Bogart’s death, that called itself “the Summit” or “the Clan,” featuring Frank Sinatra, Sammy Davis, Jr., Dean Martin, Joey Bishop, and Peter Lawford; they appeared together on stage and in films in the early 1960s, including the movies Ocean’s 11, Sergeants 3, and Robin and the 7 Hoods (in the last film, Bing Crosby replaced Lawford). Sinatra, Martin, and Davis were regarded as the group’s lead members.
 
1950s
The name “The Rat Pack” was first used to refer to a group of friends in New York. Several explanations have been offered for the famous name over the years. According to one version, the group’s original “Den Mother,” Lauren Bacall, after seeing her husband (Bogart) and his friends return from a night in Las Vegas, said words to the effect of “You look like a goddamn rat pack.” “Rat Pack” may also be a shortened version of “Holmby Hills Rat Pack”, a reference to the home of Humphrey Bogart and Lauren Bacall which served as a regular hangout.