The past two decades have seen a growing interest in the role of humor and play in second-language (L2) learning and teaching. Drawing on the methods of conversation analysis, discourse analysis, and sociolinguistics, researchers have sought to understand how teachers and students "do" humor and play, what functions humor and play serve, and ultimately, what such practices might mean for language learning. The purpose of this paper is to bring together the growing body of work that addresses various forms of playful talk in language classroom interaction, commonly labeled "humor," "language play," or "humorous language play." Following a brief sketch of how humor and play have been conceptualized in applied linguistics, this article discusses several classroom-based studies conducted over roughly the past decade. The author focuses on specifying what has been learned about the forms that humor and play take in the classroom, or how humor and play are done; the social functions that playful classroom talk serves; and how humor and play may be connected to language learning. The aim of the article is to provide a snapshot of the state of the art and offer suggestions for future research.