I have been trekking nearly for a decade now and all those years I have never had a tent with me. It was roughly a couple of years ago, I bought my first tent. :-) I had always relied on natural caves and structures. Sometimes I still do.
It was very recently that I had gone for a long jungle trek with a fellow and we were supposed to reach a cave before sunset. But we got stranded and would have had to stay up in the middle of nowhere in the forest. We had all the stuff except for a shelter. So I could somehow manage to get an idea of where we needed to go and then we set a small campfire, cooked our food and walked into the forest to reach the cave something around 3 am.
This idea still tickles me what I could have done, or anybody can do, to make a shelter without wasting much of the time and energy, especially when it's raining. Has anybody tried making a kind of thing that comes closer to what a tent looks like?
On a personal note, I would love to try that instead of staying up in a tent.