Some of my more interesting places:
Fingered a girl once while she was lying in a hospital bed. There were 3 other occupied beds in the room... the curtain around the bed was mostly closed... but it was interesting nonetheless. She managed to keep quiet. Heh.
Out in a field of 2 foot high grass, with a well used path some 50 feet away. We were using a flattened patch of grass that was apparently used more often. We were both nervous about someone walking to our spot.
In the mediterranean sea, during the day. with people on the beach and in the water everywhere. It wasn't very long... it was more of a proof of concept than getting eachother off.
At night under a cloudless sky with a full moon on a beach in Ghana (country in Africa, for the geographically challenged).