Some many years ago I started a Sour Dough Starter and it was active for about 7 years. Then we moved and I never got it going again.
I love sour dough bread, rolls and pancakes but it takes some time and preparation to make. In ye olde days the starter was made by combining a ball of dough with a little milk or just water, covering the ball with a cloth and letting it "ferment" in the kitchen.
In modern times a sour dough starter can be made with a packet of bread yeast, nonfat dried milk, flour and a jar, but the basic idea of letting yeast grow in dough and using that to seed a loaf of bread.