We do what we can, homestead-wise, in the backyard of our small urban lot: Chickens, rain barrels, vegetable garden and fruit trees, line-drying, composting, etc.
It's not enough to save us come the zombie apocalypse, but we are self-sufficient in little, satisfying ways: We don't ever need to buy garlic, green onions, spaghetti squash, rosemary, oregano, or flowers for the table. We enjoy watching the bees, butterflies and hummingbirds that come to visit our borage, sage and lemon verbena flowers. When the stars align, we can make whole dishes out of the garden using fresh chicken eggs, new potatoes, salad greens, eggplants, apples, boysenberries, etc.
My current project is guerrilla gardening the neighborhood a bit more: olive trees, pomegranate seedlings, figs, etc. will probably survive in some of the oddball strips of unsupervised public land around the freeways and runoff channels that cut through the neighborhood.
We added rhubarb to the parking strip this year and it seems to be going gangbusters. Maybe next year we can harvest some for my mom to use for her killer strawberry-rhubarb pie.
In short, it's mostly a hobby but even if it's not perfectly remunerative, it's terribly rewarding just the same.