This exercise gives the group practice in interpreting body language.
Get a volunteer to stand in front of the group. Ask the volunteer 10-20 questions such as: 'Do you have a dog?', 'Are you married?'. The volunteer should answer the questions correctly with a simple 'yes' or 'no';. The others watch carefully. Then ask 10-20 different questions with the volunteer only thinking the answer no sound. The group must guess the answer based on the body-language signs they have observed.
Have two preliminary rounds in which the volunteer answers all the questions correctly in the first round and all the questions falsely in the second round. In the third round the vounteer answers some questions correctly and some questions falsely. The group has to determine which answers were true and which were false.