8 cups of whole milk. You can use organic (we did!) milk, but make sure that it is not "ultra-pasteurized"
1/2 cup of plain yogurt with live, active cultures. Again, you can use organic (we did!)
a heavy bath towel
Pour milk into the crock pot, and set it to low. Cook for two and a half hours. When time is up, turn off your crock pot, and let it sit for three hours. No peeking! When three hours have passed, remove two cups of the warm milk and whisk it with your store bought yogurt until it's well blended. Pour everything back into the crock pot, and whisk it together until it's good and mixed. Put the lid back on, and wrap the entire crock pot up in the bath towel. Now go away for 8 hours. Seriously. Don't touch it. Go to sleep, or go to work, or go somewhere - resist the urge to peek inside.
When 8 hours are up, you will have yogurt! It will be kind of watery. If you like thicker yogurt, chill it in the fridge overnight and in the morning, strain through a cheese cloth. The end result will be thick, creamy, delicious homemade yogurt.