It's not the beginning of a joke, it actually happened. Doctors often have music playing in an operating room because it helps them to concentrate and has been shown to calm patients before surgery. However, it's not every day that the music provided comes from the patients. While there have been some instances of patients undergoing surgery and performing songs on instruments or singing and reading music, it's fantastic every time it happens. Recently a woman in Texas underwent awake brain surgery for a tremor in her hand. The shaking of her left hand had been a problem for years, as an inherited condition left her struggling to play the flute.
During the surgery, she had deep brain stimulation, where electrodes were implanted deep in the cortex. The doctors asked her to move her hand in different ways to see if the electrodes were working in real time, so she held a cup of water and drank from it to gauge the results. The ultimate test, however, was asking her to play a song on the flute. The music filled the OR, and when she was done, she received a round of applause from the surgical team.