This episode has examples of the following tropes:
Delayed Reaction: Edith, always slow on the uptake, doesn't realize until her new friends, Curtis and Ruth Rempley, arrive at the house that they want to swap spouses.
The Bunkers make a load of unintended sexual ones like asking the Rempleys what they did for fun;
The Rempleys, however, make a purposeful one when they mention they're "trophy hunters" (meaning they won trophies in various swing dance competitions).
Double Take: Edith, when she finally realizes what Curtis and Ruth wanted ... and her struggle to express her rejection of their lifestyle when Ruth tries to explain. Mike, Gloria and Louise have had past run-ins with the Rempleys and know immediately what they want.
Polyamory and Swinging: The Rempleys' lifestyle, rationalizing that they needed it to save their marriage.
Pun: The Rempleys are swingers in both the dancing and the lifestyle meanings of the word. Edith actually notes, when they say they won the Harvest Moon Dance Contest, Foxtrot Division, that they made the New York Daily News.
Weasel Words: The Rempleys' magazine ad, starting with it being in the "swap" section ("where they swap unusual things", according to Edith) of the classifieds, and ending with them saying they "wanna swap good times".
