Most of the jokes are just a bit of fun. I tend to change the subject instrument according to where I'm playing. However, never knock humble instuments like the Kazoo as I once managed to get a band of severely disabled people together to play at a "concert" hosted by musicians from a well known orchestra. They were amazed and so was everyone else except one pratt who made one or two comments about mentally disabled people having no sense of music. They enjoyed it and so did I. I later threatened to use my banjo on his head.
The best "music " joke I ever heard was in the days of Idi Amin - remember him? - who was shown on TV forcing his government officials to listen to him "playing the melodeon" I heard someone remark " Well he wasn't all bad then"
Keep the jokes coming