Your background is reassuring for cheese-makers, Penny. leeneia worries a lot, but having the answers for those concerns is what makes some of these food threads very helpful.

I make yogurt, and sometimes I put it in cheesecloth and let it hang to get to the consistency of ricotta/soft cheese and use it like fresh cheese, in lasagna, etc.

There are several recipes I've seen for milk left to set in a warm dark room. My mother talked about her step-mother making something like that (a Norwegian recipe) - I think it was clabber. There are lots of sour milk and sour cream recipes out there.