We have a church just down the street, and when church lets out, congregants file past our house to their parked cars.
Today in the large city park just down the street, several organizations pooled their resources and hosted an international festival. Throughout the day people filed past our house between the festival site and their parked cars.
My children, entrepreneurial hustlers that they are, recognized the serendipity of church letting out and festival-goers filing past our house simultaneously. This coalescence prompted them to put up a lemonade stand to quench the thirsts of the weary passersby.
Their operating a lemonade stand was a needed public service. They would have been neglecting their duties as responsible citizens to have done otherwise.