There are hundreds of details that go into the making of any successful game (on any platform), but the most fundamental question is, "What makes this fun?" This session will uncover the basic needs of various audiences when it comes to play and look at why play is an important (and basic) human need. Moreover, based on recent global research, we will present a typology of the core play patterns that can be invoked when creating games, and why and how those make for engaging interactive experiences. Although grounded in theory and research, the goal of this presentation is to be both an inspiring and practical guide for making PLAY the basis of user-centered design.