This research aims at analyzing the co-construction of conversational humor considering its different aspects such as teasing, play or irony. It is a qualitative research based on the concepts of Interactional Sociolinguistics and Conversation Analysis, which traditionally analyzes language in use. The paper investigates the co-construction of play frame (Bateson, 1972), considering its overlapping and layering (Goffman, 1974, Tannen & Wallat, 1987) and the contextualization cues (Gumperz, 1982). It analyzes preference organization (Sacks, Schegloff & Jefferson, 1977) taking into consideration the concepts of an accountable, sanctionable and not sanctionable act (Boyle, 2002). It also investigates the relation between frames and involvement strategies - repetition, imagery and constructed dialog (Tannen, 1989). The data collected consists of sixteen hours of audio recorded conversations among eight friends during informal lunches in the city of Rio de Janeiro. The results indicate a necessary shared knowledge when the play frame is to be accepted. When there is a lack of shared knowledge, the play frame is not accepted, which can lead to a conflict in the interaction. In intentional layering of frames, play can work as a strategy to hide another frame. As to preference organization, taking into account play directed to one of the participants of the group, dispreferred sequences, which are characterized by a break of expectations, are highly evidenced. A high use of involvement strategies in the acceptance of play frame seems to contribute to the promotion of solidarity among participants.