This is for contexts in which a song's lyrics are at least partly made up on the spot.
- The 2013 CBC movie Jack portrays Jack Layton as singing a politics-themed version of Home On The Range on a campaign bus when one of his campaign staffers injects his own lyrics spontaneously:
Jack Layton: Please vote NDP; stuck in third place now for years; and it stinks on this bus, there's 47 of us...Campaign staffer: ... and Jack's singing is hurting my ears!
- In Home Movies, an entire song and dance about Rice is made up on the spot.
- The lyrics to Deep Purple's Smoke on the water were made up in about five minutes flat because they were running out of studio time and needed another song to fill up the LP with. Allegedly.
- In the musical Adrift in Macao, a new lounge singer is forced to sing "Pretty Moon over Macao", even though she doesn't know the song. She at least rhymes.
- In Who Framed Roger Rabbit, detective Eddie Valiant made up a silly song to get the Weasels to laugh themselves to death. When he couldn't think of more lyrics, he switched to an equally silly dance. It worked.
- In Star Trek: Voyager the Doctor was performing a recital of La Donna e mobile when Tuvok suddenly starts experiencing pon far. The Doctor starts singing improvised lyrics to the same aria to calm and distract Tuvok so he can be sedated.
Doctor: Tuvok I understand/You are a Vulcan man/You have just gone without/For seven years about/Paris please find a way/To load a hypospray/I will give you the sign/Just aim for his behind...
- The songs on Whose Line Is It Anyway are made up on the spot.
- There are three impov companies in Chicago that nightly put on an entire improvised musicals.
Hello, Unknown Troper. You'll need to get known to lend a hand here.