Everyone walks around blindfolded. When you bump into someone say ";Pruise?"; If they say ";pruise?"; back to you then they are not the person you are searching for and you continue searching amongst the crowd. The leader has whispered to one person, telling them that they are the Pruise. The Pruise who isn';t blindfolded removes a players blindfold when they find him they then still walk around but remain silent when bumped into. The game continues until everyone has found Pruise.
Source: From the original site.