The Set Up: At every turn, Franz Liebkind, the Hitler-worshipping neo Nazi, pines for the good old days of Nazi Germany and showers posthumous praise on Hitler.
The Gag: "Hitler... there was a painter! He could paint an entire apartment in ONE afternoon! TWO coats!" beams the Fuhrer-loving Liebkind.

The Producers, Gene Wilder, Kenneth Mars, Zero Mostel, 1968. Photo Courtesy of the Everett Collection.