Peer instruction is a well-established educational technique that challenges students with conceptual tests which are solved alone and then debated in groups. It is quick and effective and can dramatically enhance student understanding and knowledge retention when used as part of a traditional lecture. Students gain the same benefits as an interactive tutorial but peer instruction scales to large numbers of students. This session will explore some of the background of this initiative but focus on the “how-to” aspect covering strategies tools and pitfalls. You will have an opportunity to take part in a peer instruction instance so please bring an internet-enabled smartphone or other device with you to the session.