(at around 45 mins) Cleavon Little was not warned about the "you know. . . . morons" line. His reaction was real.
Mel Brooks never told Frankie Laine that the theme song "Blazing Saddles" was for a comedy. Laine thought it was a dramatic western. Brooks was worried that Laine wouldn't sing it with conviction if he knew the truth.
Hedy Lamarr sued Mel Brooks over the use of the name Hedley Lamarr and settled out of court. Brooks said he was flattered by this attention. The reference to suing Hedy Lamarr was from Harvey Korman's first day on the set and, ironically, made a comedic reference to what was at that point a non-existent lawsuit.
When the film was first screened for Warner Brothers executives, almost none of them laughed, and the movie looked to be a disaster that the studio would not release. However, Mel Brooks quickly set up a subsequent screening for the studio's employees. When these regular folks laughed uproariously throughout the movie, Warner Brothers finally agreed to take a chance on releasing it.
Gene Wilder and Cleavon Little quickly became friends on-set. Since Little was a Broadway actor, Wilder would give him pointers for acting in front of the cameras.
Count Basie: (at around 25 mins) Leader of the jazz band in the desert. The song being performed is "April in Paris," written by Vernon Duke and E.Y. Harburg in 1932. The arrangement Basie played in the film was made in 1955 and recorded by him at least twice, first as an instrumental, and then at the 1956 Newport Jazz Festival with a vocal by Ella Fitzgerald.
Mel Brooks: (at around 1h 10 mins) In the outlaw recruitment line, smiling and wearing an aviator's costume. Also portrays the Governor and the Indian chief.
Mel Brooks: [producers] (at around 1h 22 mins) The music played when Lily Von Schtupp's (Madeline Kahn) poster comes on, is the first four measures of "Springtime For Hitler" from Brooks' previous movie Les Producteurs (1967), played on an old-time saloon piano.