Basic unusual places would consist of those such as: In a bush. Under a table. The bathroom floor.
There are however extremely unusual places to go to sleep such as: On top of the fridge. In a cardboard box, in the middle of a stairwell. On a traffic island. Standing up, in a mosh pit, next to a stereo cab, at a rock gig.
Against all odds, it happens. To some more than others.