Channel Hop: The radio show moved from NBC to CBS in 1949, one of a number of shows and personalities that the latter network "raided" from the former.
The show had jumped around quite a bit in its radio days: starting on NBC Blue (later ABC) in May 1932, it moved to CBS that October, then to NBC Red (now NBC) in March 1933. It went to NBC Blue in October 1934 and back to Red in October 1936, where it stayed until the great talent raid of 1949.
Also, the TV show moved from CBS to NBC for its final season in 1964.
Barry Gordon (best known as Donatello) played Jack as a child in a different episode, as well as an actor cast as young Jack in another.
Irony as She Is Cast: In real life, Jack Benny was actually a very good violinist. It takes a lot of musical talent to be able to play a musical instrument badly for comic effect and having it come out amusing rather than painful.
The Pete Best: Several people from the early history of the show. Don Bestor, Johnny Green, Frank Parker. The best example is his writer Harry Conn. Harry Conn was Jack's writer until mid-1936, when he claimed that Jack had no talent of his own and all of his laughs came from his head. Coupled with his wife making a similar remark to Jack's wife Mary Livingstone (i.e., that Mary could only afford her fur stole through Conn's talent), he was fired and left Jack without a script. Jack hired two writers named Bill Morrow and Ed Beloin, who greatly refined the show's humor and the characters into what we recognize until the end of the show. Harry Conn barely wrote anything after leaving the show and wound up as a doorman.
Talking to Himself: One episode featured Jack and Rochester taking a road trip to Palm Springs. A scene in a gas station featured Mel Blanc playing the gas station attendent, as well as providing voice overs for the Maxwell's motor and Polly, Jack's parrot.
Throw It In: That's what Mel Blanc did when the sound effect recording for Benny's Maxwell failed to play on cue. Thinking fast, Blanc took the mike and improvised the sounds himself. The audience loved it so much that Benny decided to dispense with the recording and keep Blanc doing the sounds himself.