From DIGG:
Brazilian bank worker Anthony Kulkamp Dias was kept conscious during an operation to remove a brain tumor, entertaining surgeons with songs from the Fab Four and Brazilian folk songs. By remaining conscious, the patient allows doctors to safely map the brain and avoid injury later on during a procedure that could compromise important brain functions.
The only way to top this is if someone channeled John Bonham during open heart surgery. Anyway, check it out:
https://youtu.be/2fIXNA_lT30