Like most of the games in this occasional series of mine, this is a well-known TEFL game and the main reason I’m the one writing about it is that I’m the one who has probably (over) exploited it more than anyone else…
It’s based on the classic game where you write something on a piece of paper, fold over the paper so that the next person can’t see (most of) what has been written so far, then pass it to the next person for them to continue the story. It’s most famous for writing actual stories and fairly well-known as a practice activities for conditionals, and I’ve also used it for telephoning, emailing, postcards, reported speech, and describing appearances.
Future clauses chain story (first conditional with “unless” etc)
First conditional consequences (speaking version)
The other 16 TEFLtastic classics with worksheets here.