Human hair is a cultural material, with a rich history displaying individuality, cultural expression and group identity. It is malleable in length, color and style, highly visible, and embedded in a range of personal and group interactions. As wearable technologies move ever closer to the body, and embodied interactions become more common and desirable, hair presents a unique and little-explored site for novel interactions. In this paper, we present an exploration and working prototype of hair as a site for novel interaction, leveraging its position as something both public and private, social and personal, malleable and permanent. We develop applications and interactions around this new material in HäirIÖ: a novel integration of hair-based technologies and braids that combine capacitive touch input and dynamic output through color and shape change. Finally, we evaluate this hair-based interactive technology with users, including the integration of HäirIÖ within the landscape of existing wearable and mobile technologies.