A great vocal warmup and focus game.
Everyone sits or stands in a circle, with their heads down and eyes closed. Start by making a repetitive sound, as an example such as “dum, dum, dum, dum.” Then encourage the pupils to think of their own repetitive sound and invite them to join in with you when they feel like it. Start to make your sound again as pupils chime in at random, adding their own sounds, humming, vocalizing, whistling, etc. until the room is filled with sound. When the music box reaches its peak, you wind down and stop, encouraging the rest of the pupils to follow, until it is silent once again.
Once they have got the hang of it, you can practice until you can make a sound that is actually very pleasing to the ear! Encourage them to listen to the other sounds around them and to try and harmonise.
We have used this to great effect as a vocal warm up to our Play in a Days. Have fun!