We do. I just bottled 8 pints that I cultured from our whole raw milk. Traditionally buttermilk is the liquid that remains after churning butter from cream. Not only does it make the best buttermilk biscuits and pancakes, you can also just drink it straight up. I really like the acidic taste. Similar to kefir.
Here's a great article one farm's family legacy of buttermilk. Check out the recipe for Buttermilk Poundcake. Yum!