M*A*S*H is a TV series which aired from the early 70's to the early 80's. It is referenced in a few episodes of The Simpsons.
In the episode "Lisa's First Word", there are some women talking about M*A*S*H during a flashback. One mentions that she misses Klinger, a man who dressed as a lady to try and get out of the war, whilst another mentions that she loved another character.
In the episode "Brother from the Same Planet", a character is seen reading a M*A*S*H comic book.
In the episode "Whiskey Business", Moe calls the suicide hotline when he's put on hold to the M*A*S*H theme song, Suicide is Painless