[Updated to include Treehouse customer reactions]
Well, just a couple of flashes. And compared to making yogurt, this is a snap.
Miss Maggie (The Hillbilly Housewife) has two sets of directions on her site for Curds and Whey--the detailed version and the thumbnail version, which makes half as much. I had only the quick version printed out, so I went with that. Although at least one person has had a kitchen disaster making this, mine turned out quite all right--edible anyway, and all I want it for is to combine with cheese and spinach for stuffed pasta shells (tonight's dinner). [Update: In other words, it was a substitute for our usual ricotta cheese. Everybody liked the shells and nobody got ptomaine poisoning or even asked "what is this stuff inside here?" So although the vinegar/powdered milk combination sounds very weird and the lump of cheese looks like papier-mache pulp, I would definitely make it again for lasagna or stuffed pasta--it was much cheaper than a container of ricotta cheese! And if it tasted nasty I would tell you so.]
These are Miss Maggie's quick directions (pasting them here because you have to scroll way down there to find them):
"Curds & Whey: In a large pot combine 6-cups of fresh water and 3-cups of dry milk powder. Stir to dissolve. Heat the milk over a medium flame until it is very warm, about 120°. This is hot to the touch, but not scalding. Stir in 1/2-cup of plain white vinegar. Allow to stand for 10 minutes. There should be a large mass of curds in an amber pool of whey. If the liquid is still milky, add another 1/4-cup of vinegar. Stir and stand again for 10 minutes. Line a strainer with a clean cloth and drain off the whey. It can be used as the liquid in bread or muffins or biscuits. Rinse the curds under cool water and store in the fridge. This recipe makes about 1-1/2 to 2-cups of curds."
If you need extra help, check out the detailed version.
And spiders beware.