Koo Koo Ca Choo
First let me say I loved this show. I fear it will fail because you have to pay too much attention to "get" it.
I have to point something out though. While it was kind of a good obscure joke only to be appreciated by people 50 or older, it was SO inaccurate I had to comment. When Laurie Metcalf said "Mrs. Robinson Koo Koo Ca Choo" and the other nurse "corrected" her and said "That's I am the Walrus", this joke has me totally confused. I got what they were going for, but I can not figure out who wrote this joke. If they were knowledgeable enough to craft this joke, how could they not know that in the song Mrs. Robinson they do say "Koo Koo Ca Choo Mrs. Robinson", making the correction somewhat silly.
Since Mrs. Robinson was released after I am the Walrus, I always thought it was an homage to the Beatles to slip that in.