As a tribute to the recently canceled I Spy (1965) the star of that series, Robert Culp has a small cameo as the drunken waiter.
The name of the third spy network, Attrocities Cruelties and Brutalities (ACB) is a direct reference to ABC (the American Broadcasting Company), which was the number-three network in terms of rankings at the time this was filmed. ABC was also historically the third network formed.
The title was inspired by another classic spy series I Spy (1965). Interestingly, that series premiered three days before "Get Smart", and that show's final episode aired two weeks following the airing of this episode.