While this isn't your traditional sourdough loaf, it's a delicious naturally leavened "infused yeast" loaf.
If you’ve never heard of yeasted water, it’s kind of magical. You get a mason jar, fill it with about 2/3 water, and add your fruit of choice to the water. I just pitted about 3 plums and lightly smooshed them in the jar. I then put the lid on tightly and put the jar in a cool darkish place for a week.
Check out the full writeup here: http://makebread.net/infused-yeast-water-bread/