Well, I'll tell you one fun item. My teenage kids are practicing the piano downstairs. I hear a very wrong note being played over and over. I yell down to them what note they're playing wrong and what the correct note likely is. My kids take this in stride -- it's just the thing that their Dad does -- ugh, it's Dad again. Then they occasionally get reminded by their music teacher that it's not normal for a dad to do that. :-)

Though I really am terrible at the Theremin, perfect pitch helps a lot there too. I can walk up to a Theremin and pretty much nail the note despite its current settings.