(Research) Playing video games together... with only one pad

At the ACOSTIC seminar, Christian Heath talked about people's behavior in museum exhibits. Paul Dourish makes an interesting parallels with people's behavior in video game arcades (participation...). That makes me think of what I wanted to do at DokiDenki: studying children playing video games (one hold the joystick and the others are commenting or helping him). The artifact could maximize coparticipation (in arcade game for instance)