Young Frankenstein and the Producers.
YF is an amazing burlesque AND tribute to the classic Universal Frankenstein films. In addition to great gags, it also has the best story of any of Brooks' movie genre spoofs, probably because of Gene Wilder's contributions. Wilder's sensitivity and Brooks' love of the belly laugh balance eachother perfectly.
The Producers is Brooks first comedy, and it nearly torpedoes his film career, because it was a flop and a controversial one as well. Despite this, it still won an Academy Award for Best Original Screenplay, an amazing achievement for any comedy.
This time, the Oscars were right and the public was wrong. I can't watch that move enough. The Springtime For Hitler number that made me howl as a kid is still funny, but now I also love that amazing first part of the film which is almost nothing but Mostel and Wilder in a small office going crazy.
"Give me back my blue blankie!"