Hawt Where is the most interesting place you've done it?

Was at some club in DC, GF at the time found an unlocked broom/janitorial closet next to the dance floor. We snuck in, locked the door, had some fun, straightened up, left the room.
Upon exiting the room we got a standing ovation (although everyone was already standing because there were no chairs nearby, so I'm not positive that it counts).

However, one of my favorite times was out in the Apalachicola National Forest, was about this time of year, air was getting a bit nippy, first date with this chick I had met at a mud bog. We were heading to a friends house for a bonfire and some beers, she asked where a particular trail went, sooo... we drove off into the woods.
Bed of the truck was surprisingly comfy, stars were out, was a good hour late.