**Abstract**

How do children interact with each other and how can interactive technology contribute? In this chapter, we are going to introduce two concepts that are currently present in the development of play tools for children: (1) interactive design, represented by toys that can integrate interactive sensors and actuators to promote new play possibilities, and (2) design for interaction, a new tendency focused on how children interact with each other and how new designs can contribute to these interactions. Through this chapter, existing works will be utilized to exemplify these concepts illustrating differences and connection points in-between. These will be followed by a series of studies of children's social interactions when under the influence of different game conditions. By looking into the fundamental aspects of design and interaction, we will discuss how play can promote positive interactions and how interactive technology can contribute to those. We aim to contribute to the establishment of guidelines for the development of new designs for interactions.

**Keywords:** children, sociability, game elements, technology, toys
