Ingredients - Makes 2 quarts
head of green cabbage (depending on size of cabbage, you might need one more)
salt
water
caraway seeds (optional)
a few strips of fine-sliced carrot or  red pepper (optional)
two wide-mouth quart sized very clean glass jars (wide-mouth is a must)
Steps

1. Remove outer leaves of cabbage and set aside.  Shred the rest of the cabbage onto a large cutting surface or a large bowl.  Sprinkle the cabbage with 2 tablespoons of salt.  With clean hands, squeeze the cabbage for about 5 minutes, until it's a bit limp.  Mix in 2 tablespoons of caraway seeds. 
2. Fill a large pitcher a quart or two of water and add 1/2 tablespoon of salt per quart.  Stir.
3. Pack cabbage (fairly tightly) into the jars.  Don't fill them all the way to the top - leave an inch or so.  Pour the water mixture over cabbage, until covered, but don't completely fill to top.
4. Remember those outer cabbage leaves you saved?  Pack a couple of them into the top of the jar and push them in around the cabbage to provide a type of air-tight environment.
5. Don't put on a lid!  Get a small glass or jar filled with rocks or marbles.  It needs to be small enough to sit on top of the cabbage leaves.  This all keeps the cabbage submerged in the liquid.  Lightly cover the top with a clean dish towel or cheese cloth and sit the whole thing inside a large bowl or pan.  The mixture will ferment and give off gas and liquid, which needs to get the heck outta there.   
6. Let sit in a cool place out of direct sun for 3 days.  Once or twice a day, remove the weight and mash everything down just a bit, then replace weight.  If the liquid isn't covering the cabbage, add a bit more salty water.  If you see white bubbles, it's OK - it's the fermentation process. After the 3rd day, then remove the outer leaves and compost or dispose.  Place shredded cabbage into a strainer rinse it very well.
7. You have sauerkraut!  Place it in a large pot filled with water and a tablespoon of apple cider or plain vinegar.  Boil for 15 minutes.  Let cool, then place in clean jars.
8. Store in refrigerator and use within a month.