This document describes an exercise used to teach undergraduate students about ableism and discrimination against people with disabilities. In the exercise, students analyze architectural barriers in campus buildings to understand how people with disabilities are excluded from everyday social interaction. By observing barriers firsthand, students link their experiences to sociological concepts of deviance, conformity, discrimination, and stigma. In their written work, students demonstrate an understanding of how physical barriers relate to social barriers and how the built environment can disadvantage those with disabilities through institutional discrimination despite laws like the ADA. The goal is for students to recognize discrimination beyond overt individual acts and to perceive more subtle institutional ableism.