This video provides an overview of the Situated Interaction project at Microsoft Research, an effort towards developing open-world interactive systems that can embed interaction and computation deeply into the natural flow of daily tasks, activities and collaborations. The video highlights project goals and reviews a prototype platform which weaves together several component technologies, including learning and inference about activities and goals, speech recognition and synthesis, vision, conversational scene analysis, and multiparty dialog management, to support fluid interactions with multiple users in an open-world context. The video illustrates several challenges and competencies with an application running on the platform, named Receptionist, that handles problems in the domain of building receptionists. More information about the project and related research are available at http://research.microsoft.com/en-us/um/people/dbohus/research_situated_interaction.html.