A random moment on the Métro in Paris, perhaps a dozen years ago, returning late at night to our apartment.
Two young people get on, carrying several carrier bags; they quickly snap a sheet across two poles and, voilà! Showtime!
The French was too fast for my ear, the singing was pleasant if not professional, and the show was over in three or four stations. Certainly worth the €5 we left. Cheap for a memory.