AFI #053 Groucho Marx as Capt. Geoffrey T. Spaulding from Animal Crackers (1930)

One morning I shot an elephant in my pajamas. How he got in my pajamas, I don't know.

- Groucho Marx as Capt. Geoffrey T. Spaulding from Animal Crackers (1930)

The bolded line is ranked #53 in the American Film Institute's list of the top 100 movie quotations in American cinema.