This chapter examines how various properties of play have inspired and can inspire new design directions for digital games and intelligent play objects. Play theories from a child development perspective are described and related to concepts from game design, such as game mechanics and dynamics. Furthermore, a discussion is provided of how different properties of play relate to children practicing social, emotional, physical, and cognitive skills in a playful and fun context. An adapted version of the mechanics, dynamics, and aesthetics (MDA) model is presented as a tool that supports considering the richness of play design opportunities when creating dynamics, mechanics, and aesthetics for diverse forms of play from a designer and a player's perspective. The exploration is extended by describing four design case studies of tangible intelligent play concepts for different contexts of use related to different properties of play.