Humor is an inevitable part of human life. Most of us are capable of experiencing and appreciating humor. From this perspective, surprisingly little HCI research can be found scrutinizing the existence, role, and potential of humor in our design practice. The gap remains also related to children and teenagers; there is a lack of studies appreciating the emergence and existence of humor in the design process without intentionally evoking it. Thus, this study examines humor as a naturally occurring phenomenon in the design process. The study was conducted in collaboration with a class of teenagers and their teachers. The study identifies various forms and functions of humor in the design process and reveals its situated, emergent nature as a resource in interaction within design. The study proposes a practical tool for designers for anticipating and potentially facilitating the emergence, forms and usages of humor as an interactional resource in design.