Nothing beats the feeling of a potent runner's high. But worrying about aching or stressed knees can dampen the euphoria. The paved rubber-mulch path at Kennedy Park is a welcome alternative to pounding pavement on an urban jog. If you want to turn that run into a full body workout, the park is also equipped with an outdoor exercise course with calisthenic equipment. And if it's one of those brutally hot days and you're not a calorie counter, you can cool down afterward with a frozen lemonade from A.C.'s Icees ($3.50 to $7), whose truck has been a fixture at Kennedy Park for more than 30 years. While you're at it, take a well-deserved break and sit on one of the many benches overlooking scenic Biscayne Bay.