"Dear Dad" (1972)
This episode does what so many episode of "M*A*S*H" did, and what every Christmas story should do: It made you laugh and cry. This was the first in a series of episodes that had characters writing letters home. Hawkeye describes Christmas as the 4077th in all its mad glory. Radar sends a jeep home in pieces, Henry delivers his monthly sex and morals lecture, and — here's the kind of image that makes "M*A*S*H" so timely — Hawkeye shows up on the front line in a Santa outfit.
Pictured clockwise from left: Mike Farrell, William Christopher, Jamie Farr, David Ogden Stiers, Loretta Swit, Alan Alda, and Harry Morgan.