I've been raising this ginger bug on the counter for the past while. Every day I feed it some grated ginger and a bit of sugar. After a week or so, it starts bubbling and becomes the basis for a batch of ginger beer. The ginger beer is dry, a little fizzy, and very gingery. Delicious! Oh, and did I mention, loaded with lactobacilli, those friendly little organisms that keep your digestive system working?
I followed the recipe from Wild Fermentation, the book, but there's a similar recipe here.