How can we effectively improve classroom interaction and engagement, particularly in large (100+) lectures? Monash University started a social classroom program in 2008, using tablet PCs to transform lecture slides into a collaborative whiteboard where students can explore and provide feedback to the lecturer (e.g., quizzes or screen submissions). Instructors have moved from a focus on content to constructivist collaboration, highlighting key concepts and opportunities for peer instruction.The session will teach participants to apply co-constructivist approaches to live collaboration tools that support peer-to-peer learning and instructor-student interaction in the classroom. Following a lively exploration of why, or whether, we need to (re)engage our students, participants can actively explore tools like Classroom Presenter, eClicker (iPads), Monash MeTL, Poll Everywhere, and others that encourage and facilitate collaborative approaches to learning and teaching. We'll also explore how best to use them in classes with 20 to 200 students.