My latest kitchen experiment is making milk kefir. Kind of like a liquid yogurt, it's easy to make in a jar on the kitchen counter - no messing with maintaining a constant warmth like with yogurt.
All you need to get started are some kefir grains. I got mine by posting a request on my local Freecycle network, but they're also available via the Internet. Tomorrow, Oz-time, is my day to post on the SGF Co-op blog, so I've written about the kefir-making process. You can read about it here.