There's one thing I did that got lots of grins: at the pre-op visit the week before, the surgeon wrote his initials on the hip to be replaced. They wore off during the week, which gave me an idea, since teams doing the wrong hip isn't all that rare (never happened at this hospital, but there's nothing wrong with being careful). So when I got wheeled in and they checked my hips, the right side had this:
C A U T I O N
* please open other side *
When the anaesthesiologist tapped it and pointed it out to a nurse, I waved my hand a little and told him, "This is not the hip you're looking for".