Since this is conversation is as much about milk as about men - has any of you ever ate "sour milk"?
You guys might be surprised, but when milk turns sour, it doesn't turn automatically bad. So lets say you bought a gallon of milk, and half was left over and now is turning sour.
You pour it into a bowl and leave it out for the night, preferably somewhere that is warm (but not hot). Now, sometimes the next day, or 2 days (this depending on what the temperature is) the milk will became semi-solid. And no, it doesn't reek at all. It has a faint sour smell, but it is not band at all.
On the top of it there will be a thin, buttery layer, that is sour cream. While on the bottom there will be whey (you ditch that)
I never ate kefir, but they say the "sour milk" tastes a lot like it.
If you want to make cottage cheese, you scrap off the sour cream, boil the milk and then drain it.
And with a little more effort, you can make cheese out of the cottage cheese.
We used this technique with un-pasteurized milk at home, but since I've been here at Uni pasteurized milk turned sour on me and it still behaved like the un-pasteurized one.