Movies You Haven't Seen But Should: A Thousand Clowns

Wiki:

A Thousand Clowns is a 1965 film which tells the story of a young boy who lives with his eccentric uncle Murray, who is forced to conform to society in order to keep custody of the boy.

The movie was adapted by Herb Gardner from his 1962 play, and directed by Fred Coe. Gardner based the Murray Burns character on his friend, Jean Shepherd, who is said to have not appreciated the gesture.

Unemployed television writer, Murray Burns, lives in a cluttered New York City one-bedroom apartment with his twelve-year old nephew, Nick. Murray has been unemployed for five months after walking out on his previous job, writing jokes for a pathetic comedian who hosts a children's television show. Nick was abandoned by Murray's sister seven years earlier, and now attends a school for gifted children.

When Nick writes a school assignment on the benefits of the unemployment system, some of what he writes about his home surroundings causes his school to send social workers to investigate his home environment. Confronted by investigators for the Child Welfare Bureau, Murray is given the option of finding a job or losing custody of his nephew. Along the way, Murray charms and seduces Sandra (played by Barbara Harris), the young psychologist assigned to Nick's case.

Although Murray tries to avoid returning to work, he finds himself in a dilemma: if he wishes to keep his nephew, he must swallow his dignity and acknowledge his greater responsibilities. When he chooses to go back to work for a man he detests, he ultimately loses the respect of the nephew he so highly prizes. However Nick also stands up for himself, telling the comedian how terrible he is. At the end Sandra and Nick begin to clean the apartment, and a more normal home life, with a stronger child, may be developing.

A Thousand Clowns on the IMDB

Nick: I can imitate the voice of Alexander Hamilton. I do Alexander Hamilton, and Murray does a terrific Thomas Jefferson. We got the voices just right.
[Murray and Nick speak to each other in normal tones throughout]
Murray Burns: [to Nick] Hi, Alex, how're you doing?
Nick: Fine. Say, Tom, you should have been in Congress today.
Leo: This is ridiculous! You can't do an imitation of Alexander Hamilton, nobody knows what he sounds like!
Nick: That's the funny part.
Murray Burns: You missed the funny part, Leo.