The Simpsons is not the only Matt Groening show to reference M*A*S*H. In the second season Futurama episode "War Is The H Word", Fry, Bender, and Leela enlist in the Army and end up on some faraway planet fighting a race of aliens that look like bouncing balls. Killer bouncing balls.
Bender is severely injured, so he is taken to nothing less than a MASH unit set up on the planet. When we first see it, we hear a take-off of "Suicide is Painless", and the unit looks very much like the 4077th. The producers even got an actor from M*A*S*H who was one of the voices of the P.A. on the original series to do the same job here!
Not only that, but we see the unit is staffed by a joke-telling, martini-guzzling robot surgeon named iHawk, who toggles a switch on his torso (labeled "Irreverent" and "Maudlin"), simultaneously paying tribute to the show while also mercilessly poking fun at it. Priceless.
I had completely forgotten about this whole scene until Swamp Rat Eric Miller reminded me of it on the Simpsons post. I guess if Matt Groening ever does another series, there'll be a M*A*S*H parody on that show, too.