Most of us will never find ourselves lost in the woods with night falling. Most of us would also not know what to do if we did end up in that situation. Luckily, there is an excellent article explaining how to build a debris hut out of materials easily found out in the bush.
A debris hut is nothing more than a pile of debris, like leaves, dry grasses, branches, and whatever else is lying around, with a spot for you to sleep and some protection from blowing away. Think of it as a tent within a tent. Build a tent skeleton from sticks, pile as much debris on as you can, add another tent of branches to keep your pile from blowing away, and you’ve got a cozy nest to sleep in.
This method could also be easily adapted for the urban environment. Paper, cardboard, and plastic wrap would replace debris, and posts, bars, lengths of wood or steel could be the structural elements. Of course, in an urban environment you’re more likely to find shelter of a more permanent and secure sort, but it’s good to have options.