So, an orchestra rehearsal is going on and the oboe player walks up to the conductor and says that the viola player just broke her reed. The conductor asks why he did that and the viola player responds, because she just turned one of my tuning pegs and wont tell me which one.
This a joke that makes fun of the viola players in orchestras. It makes fun of the stereotype that viola players are the worst musicians in the sting section and that because of this they are often unable to tune their own instruments. This is a popular joke among musicians because we need something to bring some laughter into a very long boring rehearsal situation.
This joke has stuck with Stephanie because she is very close friends with a very good viola player at USC and she is an oboe player. The joke is popular in a broader sense because it can be adapted for many different string instruments and reed instrument combinations. I have hear the joke before and it has been told to be with and oboe player and a cello player, a clarinet player, and a violin player, and with a bassoon player and a bass player.
The ability for this joke to be adapted for many different instrument combinations makes it more accessible to other musicians that just oboe players and viola players. This means that it is more likely to be retold in variations which will help keep it popular among musicians.