There was no plain yogurt at the grocery store last week so we tried kefir instead. I've looked at it before but really had no idea what it was (and there was always plain yogurt available). It turns out it is pretty good stuff.  I've only had it with granola so far. It's sort of halfway between milk and yogurt. It coats the granola but is still runny and has a really nice tanginess to it. It's also, and I found this very weird and cool, very slightly fizzy.