After recently watching a copy of Casablanca that I forgot I had, I looked it up on IMDB.com and found this bit of trivia about Humphrey Bogart: "Frank Sinatra's friends, known as The Clan, were originally a group of Bogart friends who enjoyed drinking heavily. They referred to themselves as 'The Holmby Hills Rat Pack', since Bogart lived in the Holmby Hills section of Hollywood. The Rat Pack name had originated one morning, after a night of heavy boozing, when Bogart's wife Lauren Bacall came upon the sodden group and flatly stated, 'You look like a God-damned rat pack.' Bogart enjoyed the term, and a legend was born. But Sinatra stopped using the "Rat Pack" name after Bogie died in 1957, and he and his friends hated it when others continued to label them that way (Source: Robert Osborne, Turner Classic Movies)." I had heard Bogie was an original member, but could not remember where I had read it.