Aha! An episode where I remember all three shows!
I still know every word of the Addams Family theme song. *makes note to find some episodes of the Addams Family to watch again* Never will I forget Cousin Itt, because one of my sisters had hair very like that. (Very long and straight, not covering her face. Usually.) And Ted Cassidy--Lurch--was the android Ruk in ST-TOS's episode "What Are Little Girls Made Of?"
You know Oliver Wendell Douglas was a lawyer not because of the three names thing, but because of the first two of those names--Oliver Wendell Holmes, Jr. was a Justice of the US Supreme Court. (Which completely went by me as a child, and I didn't remember his name until Bob mentioned it, and then I started jumping up and down--well, mentally, anyway.)
I wonder if Mel Brooks took the orchestra-on-the-bus in High Anxiety from the music from nowhere on Green Acres?
Just for a giggle, take a look at this post from Poetry and Popular Culture on Herman Munster's poetry (you heard me):
http://mikechasar.blogspot.com/2010/08/herman-m...
(Although I can see the show as making a very sneaky comment about judging people by their appearance. Still...!)