Multi-Mouse Quiz System consisting of Multi Mouse Quiz (MMQ) and MMQEditor is an application set to treat quizzes in a classroom. The MMQ is an application of Single Display Groupware (SDG) which enables multiple users to answer quizzes by connecting several mice to an ordinary personal computer (PC). The MMQEditor is a PC application designed to edit quizzes for MMQ. The authors have asked several elementary schoolteachers to use the MMQ system and observe the class activities. The class practices show that the schoolteachers designed various class activities and quiz content along with the context of their school and class. This paper reports these practices from viewpoints of class design, their effectiveness and problems. We also discuss importance of collaboration among schoolteachers who design and practice class, and researchers who develop the system and analyze the class activities learnt through this study. © 2013 Springer-Verlag Berlin Heidelberg.