My understanding is that banjo jokes are needed because the banjo requires a lot more tuning than most instruments. In my experience, the jokes are usually told by the fiddler (who practically never tunes) to while away the time while the guitar player helps the banjo player tune. That way the audience hardly notices that everything has ground to a halt while the banjo player tries to get somewhere close to the key that everyone else is playing in. Perhaps Bill or Art (or any other banjo player) could expound on the technical aspects of why this is so. I have my theories gleaned from some of the banjo players that I know, but I certainly would not venture to put them in print with so many banjo players around who know a lot more than I do about it.

Here is a banjo player's joke. What is the difference between a fiddle and a kazoo? ~~ You don't need a bow to make funny noises on a kazoo.