Ambient systems leverage mediums such as colour, shape, form, and motion to convey meaningful representations of information in the periphery of the user. This allows users to attend to several streams of information outside of their central attention without invoking additional cognitive load. While previous work explored how this paradigm might enable the user to take on a greater load of practical information, comparatively little work explored the potential this holds to mediate casual social interactions. In this paper, we examine how playful and abstract ambient interfaces leverage ambiguity and curiosity to create unobtrusive peripheral interactions that mediate and facilitate social interactions. We discuss the design and implementation of AmbiDots, an ambiguity-centric ambient system that uses subtle, coloured dots to support peripheral playful interactions in social settings like cafes, restaurants or bars. Our study demonstrates how this system enables various forms of social appropriation without disrupting social interaction.