I got some kefir grains today, and have it fermenting a small quantity of milk to see what it’s all about. According to this guy, kefir is literally the food of the gods, with links to the manna that fed the Jews on the Exodus and to Mohammed.
It’s not really a grain, but an kind of organic matrix of simple yeastie beasties that ferment dairy and non-dairy liquids into a mildly alcoholic and highly nutritious brew. If the stories are accurate, all the kefir starters alive today can be traced back to the efforts of a brave Russian girl and a couple of resourceful Russian businessmen in the earlier days of the last century, and perhaps back to biblical times.
I do have a mild fascination with living foods — yeasts, yogurts and the like — so it makes sense to look into this. Putting kefir into the Google returns a lot of pretty enthusiastic results. More info as it, er, develops.