This chapter investigates how to create ad hoc audience response systems using nonspecialist devices. The chapter revolves around two case studies: one involving the use of mobile phones, and the other based on PDAs. Both case studies are carried out in tertiary education institutions, showing how these devices can be used to facilitate audience participation using devices that students might, themselves, bring to lectures. Both are evaluated from the perspective of the student and the educator, using a mixture of observational and interview-based techniques.