The baseball card Danny shows Laurie's boyfriend is a 1972 Topps #300 Hank Aaron In Action (although his name was airbrushed out).
The title is a parody of the Ian Fleming James Bond novel "You Only Live Twice" published in 1964 just before Mr. Fleming's death.
Bruce Kimmel's first of two appearances as Richard Whipple, but third of his five total appearances.
The board game Keith, Laurie and Danny are playing at the beginning is "Monopoly."
When Shirley addresses Danny as "Howard" when he doesn't want to quit playing the Monopoly board game as "Howard," it was a reference to billionaire Howard Hughes.