Years ago, when two of my friends and I were leaving a nightclub, as soon as we stepped outside the door, we saw a car that was parked close to the entrance, and all the windows in this car were fogged up. But even through all of the fog, we could still see the bodies of two people in the backseat who were having wild sex right there in plain sight.
The female was sitting in the male's lap, riding him like she was a cowgirl riding a rodeo bull. Apparently, they didn't care who saw them. They were most likely drunk--which may be what led to their horny little episode. My friends and I just tried to walk past the car as quickly as we could so the couple wouldn't think we were watching them--even though they probably didn't even notice we were out there, being that they were a little busy at the moment.
Either way, although I'm sure that people have seen worse things outside of nightclubs, this was the first time I'd ever seen anything like that.