The couch gag pictured the Simpsons and the Flanders as figures on the Bayeux Tapestry, centuries-old, 230-foot long embroidery that recounts the story of the Norman Invasion of Britain in 1066.
I learned about the Bayeux Tapestry as a kid in history class in the UK, and saw its modern counterpart -- the Overland Tapestry -- in the D-Day Museum in Portsmouth. The original, or what's left of it, is under glass in a museum in France.
Here's the Simpsons' version:
Watching this confirms two things: I am a die-hard Simpsons fan, and I am a geek for history.
Alas, the Simpsons' writers had to malign my profession later in the episode. Thanks, Nelson.
I know the clips look the same -- the picture shows a Simpsonized version of Jon Stewart. Once you hit play, different videos will start playing. Enjoy.