As of last week, they were sold-out, but the two "All About Kombucha" classes at the Brooklyn Kitchen still have a few slots. One is tonight, Tuesday, at 6:30 p.m., and the other is the same time tomorrow; both are $30. Read up on kombucha, be mesmerized by its creepy/awesome fermentation qualities (it has a mushroom-shaped mother?!), then go to the class.