Realism of rendered human skin can be strongly enhanced by taking into account skin wrinkles. However, modeling wrinkles is a difficult task, and considerable time and effort are necessary to achieve satisfactory results. This paper presents a simple method to easily model wrinkles on human skin, nevertheless taking into account the properties of real wrinkles. Wrinkles are specified using intuitive parameters, and are generated over a triangle mesh representing a body part, such as a hand or a face. Wrinkled skin surfaces are rendered at an interactive frame rate, dynamically modulating wrinkle amplitude according to skin surface deformation while animating the body part. We demonstrate the ability of our method to model realistic wrinkle shapes by comparing them with real wrinkles.