Try and guess what the next person has done, will do or just guess something about them. Then the next person replies whether it is true or false, then predicts something about the next person, and so on. Example:
Bob: TNP has 2 cats Jim: True. TNP will jump off a building PHD Bling: False. TNP once won a medal. ...and so on.
TNP stands for 'the next person' or 'the next person' etc.