Not a flight deck announcement but a memorable moment...
On what is normally a 15 minute flight from YVR to YYJ.....All passengers aboard but after 10 minutes, still no engines running . Flight Attendant standing at the top of the stairs looking out.... and passengers getting restless.
And then the FA says, "Two gentlemen are about to board and then we'll be departing. Please clap and give them your most enthusiastic welcome."
Greeted by applause, cheers and whistles as they came up the stairs, were a very harried looking (and surprised) Captain and First Officer. As the Captain was entering the flight desk, he turned back with a grin and said, to the passengers, "I should have known something was up, I've never seen her smile before." (referring to the FA)