When touring in provincial England, Adler used to do the following stunt.
Extremely cheap plastic mouth-organs would be given out free to the
audience. At some point in the show, a shill in the audience would wave his
free gift in the air and call out in a tone of disgust: “You don’t really
expect us to be able to play anything on THIS piece of rubbish, do you?”
Adler would ask for the man to bring his free gift up to the stage, take it
off him, and give a virtuoso rendition of “The Flight of the Bumblebee” (or
some such) on it.