RORY: Well, Madeline and Louise, Paris’ best friends, they said hello to me the other day.
LORELAI: Really? Like a normal hello? Not like a “Here’s Johnny” kind of hello?
Another reference to the horror film The Shining, earlier discussed. In one memorable scene of the movie, the sanity-challenged Jack Torrance hacks through a bathroom door with an axe in an attempt to kill his wife and son. Jack Nicholson, who played Torrance, adlibbed the line “Here’s Johnny!”, which he shouts in a terrifyingly deranged manner with his head through the broken door. It is regarded as an iconic film moment.
Jack Nicholson took the line from the long, drawn-out catchphrase used by Ed McMahon when introducing the host on The Tonight Show Starring Johnny Carson, which ran from 1962-1992. It’s one of the best known catchphrases in history.