This multidisciplinary project-based course explores the design and evaluation of HCI technologies and environments that aim to change users’ attitudes, emotions, or behaviors. In addition to exposing students to an array of psychological theories and strategies for implicit and explicit persuasion, the course will cover a variety of themes and topics illustrating both the pitfalls and possibilities in designing for impact in HCI. During the last two-thirds of the course, students will iteratively prototype, implement, and evaluate a system or a change to a ubiquitous computing environment that intends to stimulate and sustain belief or behavior change (such as reducing cognitive or social biases, engaging in healthy or prosocial behaviors, or resisting other persuasive forces one encounters on a daily basis). This course is strongly multi-disciplinary and appropriate for students from diverse backgrounds, including computer science, psychology, social and decision sciences, visual and performing arts, business, engineering, and humanities. There are no prerequisites, but students should have experience in at least one of the following areas: programming or web development; rapid prototyping; graphic design; creative writing; game design; or prior coursework in social psychology or marketing.