What is the joke that goes with the punch line that Data remembers when he gets his emotion chip?

Question

Star Trek: Generations (1994)

Data: I get it! "The clown can stay, but the Ferengi in the gorilla suit has to leave!" I get it!

Answer 1

There actually was not ever a joke like this in any episode.  They were using it to set the premise that now that he has the emotion chip he can actually laugh, even if what he is laughing at is not funny.  The key that let you know this was the fact they were using lingo exclusive to the series in the line.

Answer 2

Good Question. I've wondered that as well. In that part of Generations Geordi asks Data when that was and Data tells him it was during the Farpoint mission. In TNG's openier "Encounter at Farpoint" there was never any part. I guess like that other person that mention maybe it was just to have Data laugh and something because of his emition chip. What was really funny at that part when its a 7 year joke and he just gets it. Although the part never really exisited.