Shortly after his retirement from the bench in 1933, Supreme Court Justice Oliver Wendell Holmes, Jr was paid a courtesy call by Franklin Roosevelt. The President was surprised to find Holmes reading Plato's Symposium -- in the original -- and asked him why he was bothering to study Greek. "Why," he replied, "to improve my mind."
Holmes was then 92 years old.
[According to some sources, the visitor was Dean Acheson President-elect Franklin Roosevelt.]