Two madrichim hold up a blanket in the middle of the room. The chanichim are split into 2 groups, one on either side of the blanket. Each group puts one person in front of the blanket. The madrichim them drop the blanket and the two chanichim have to shout out eachother's names. The first one to shout out the other person's name takes that person to join their group. This continues either until everyone is in the same group, or until you've had enough!