One person stands facing the wall away from the rest of the group.
Someone is picked to say "Apple Pie" out loud in a voice different to their own.
The person standing facing the wall turns round and tries to guess who said "Apple Pie"
If they do not guess correctly then the process is repeated with someone else from the group is chosen to say the word.
This is an excellent exercise to create different voices, experimenting with voice tone and quality. It can also be used to find different characters and could be used to create a short scene. For example 3 voice types could be selected and Incorporated into a scenario. The type of voice can give clues to the persons character or even a particular scenario. A brainstorming exercise might be a good tool to explore this.