Good news for those who want their ice cream to be challenging and stimulating as well as compulsively lickable. New Amsterdam Market’s “Ice Cream Sunday” on August 21 brings together, in one parking lot, ten leading lights of the frozen-dairy world, each of whom will dazzle the crowd with up to four flavors. Twenty-five dollars buys you eight mini-cones; $35 gets you ten plus the right to cut the line. Some flavors from last year’s event: sweet corn, fresh ricotta, duck egg, and hay. Which is not to say that peanut-butter-and-chocolate is out of the question (South St. at Peck Slip; newamsterdam-market.org for tickets).