Recently we camped with friends and the boys' tent came without poles. I did this out of necessity but it worked like a charm. In fact a small tent with no poles is now part of my hiking gear/ Go Bag (which you can see here), since it weighs very little.
I apologize if this is way too obvious, but when I looked up the subject I saw an Instructable that involved 100 feet of cordage and is an impressive feat of engineering for sure, but it seems like more work than most frustrated campers would want to do.
So here it is. I can add more detail and pics if needed.