This is a round-robin type game. You start out by creating a character name and a little something about them, then you introduce the next character. I'll start us off with this:
Amelia Davis is a 21 year old mother of one who lives in Rhode Island. She has a sister named....
Then, the next person would write a little something about the brother, then introduce another character. This can go on forever. Make sense? have fun writing!