A friend who was born in the 50's once joked, "I always felt sorry for my friend, Susy, whose parents had sex six times! My parents only did it twice." (At first, I thought she was serious, she said it with such disdain for the idea of her parents "doing it.") Thankfully, the only evidence I ever observed of my parents having you-you-know-what was my eight siblings.
As far as nudity, I was only mildly traumatized about seeing my dad naked by the bathroom light now and then, in the middle of the night, as we passed each other in the hallway on the way to/from the bathroom. I remember being more disturbed by his lack of modesty than by the actual appendage. In my memory, Dad was always a happy, dopey drunk (it was when he wasn't drunk that we did our best to avoid him), so he would fart, burp, mumble something like, "Ooops!" and teeter his skinny butt back to bed.
We did have a couple in our neighborhood who were notorious (among the kids in the neighborhood) for liking sex (a lot). If you hung out with their kids and slept at their house, it was rumored you would get an earful at one point or another.
So, do you have any stories about on this subject? I'm thinking some of you probably have some good/funny ones...