An old-fashioned lemonade stand went up Friday on Maple Street, not far from the City Park, as sisters Kassiey and Brianna Rook were showing their entrepreneurship, beckoning passersby to beat the heat. They also were selling chocolate chip cookies. Brianna, 9, said this was the second time they have sold lemonade on a hot day, and both times business has been reasonably brisk. Kassiey is 7 years old and both attend Dorr Elementary School.