Well I'll be. I just ran across a recipe for making yogurt in the crockpot. It's from the blog A Year of Crockpotting.
My mom always made yogurt when we were growing up and she recently loaned me her yogurt maker.
This recipe for making it in the slow cooker seems very easy although you do need to be around to monitor it. The only ingredients you need are milk and some plain yogurt from the store, and some fruit if you want to add that.
Yogurt can be substituted for a lot of things in recipes, so before I make a bunch I need to find out some of its different uses!