This study examines how students' disruptive behavior occurs while the teacher is carrying out a formal class activity--checking homework. In daily classroom life, it has been common that teachers often follow the most uninspiring teaching method when checking homework (the teacher reads out loud each item in an exercise and then asks students for the answer), which students find boring. In this study, the author looks at the teacher's verbal expressions and embodiments, ones that potentially cause a lack of students' interest in the current class activity, and the students' nonverbal disruptive behavior, constructed by those who do not comply with the classroom's norm of appropriate participation. Using an analysis that combines both talk and the body, the author demonstrates how the students' disruptive behavior occurs alongside the teacher's checking homework activity. The author then discusses how mundane class activities such as checking homework can be boredom for students, and how this boredom can potentially lead to students' disengagement. The author then calls for changes in the checking homework activity to make it more interesting for students.