There are many delightful reasons to visit the worker-owned cooperative foodie wonderland that is the Rainbow Grocery, including amazing arrays of tempting toiletries, beckoning baked goods, and seductive sandwiches, all natural, organic, vegetarian, environmentally aware, and health conscious. (Plus we like the big WORKERS ONLY signs in black and yellow over various doors and storerooms, which keep us nonworkers in our place.) But we never fail to visit two sections of the store, conveniently close to one another, to score a lovely little snack: an olive of the day (offered, one assumes, to further bolster the observance of the sign — "We are no longer able to allow self-service sampling in order to keep our products as sanitary as possible" — posted over the adjacent olive selection), and a sample of the cheese of the day. On a recent afternoon, the French sun-dried olive (or two) that we speared (with a fresh toothpick each time) was a perfect complement to the cube (or three) of Campo del Montalban, a mix of goat, sheep, and cow's milk cheese that, another helpful sign tells us, was considered a Manchego until 1985, when by law Manchego was defined to be a 100 percent sheep's milk cheese. Tasty and smart.