Calisthenics is a form of strength training consisting of a variety of movements that exercise large muscle groups such as standing, grasping, pushing, etc. All of the exercises performed in the genre are used with body weights.
The benefits of calisthenics are low cost and available to do anywhere. Calisthenics is known for excellent conditioning and muscle toning.
The difficulties of calisthenics are the slow progression made from it. Since it's all bodyweight exercises, it can be tough to accomplish the advance tasks. When you do achieve difficult challenges, the benefits are rewarding.