Within '"communicative language teaching," "natural" language has had a privileged position, and a focus on form has been seen as something inauthentic or as something that is inconsequential for learning (for a critique, see Kramsch and Sullivan 1996; Cook 1997). Yet in the present study of an immersion classroom, it was found that children with limited L2 proficiency recurrently employed form-focused language play in spontaneous peer conversations. Our work involves a distinct focus on multiparty talk, and it is shown how language play is, in many ways, a collaborative affair, initiated by the children themselves. Playful mislabelings and puns often generated extended repair sequences that could be seen as informal "language lessons" focused on formal aspects of language. Simultaneously, shared laughter and shifting alignments between peers were central aspects of the local politics of classroom life. The joking was quite rudimentary. Yet it included artful performance and collaborative aestheticism, involving alliteration and other forms of parallelisms, as well as code switching, laughing, and artful variations in pitch, volume and voice quality. The paper illustrates the need to integrate language play in models of L2 learning.