The SCALE-UP (Student-Centered Activities for Large Enrollment for Undergraduate Programs) project was developed to implement reforms designed for small classes into large physics classes. Over 50 schools across the country, ranging from Wake Technical Community College to Massachusetts Institute of Technology (MIT), have adopted it for classes of various sizes. This article discusses the classroom design and teaching techniques that allow pedagogical advances such as SCALE-UP to be used in large-enrollment classes. (Contains 6 figures.)