Write a collaborative story with one friend or more by writing a paragraph and then passing it on to the next person. You can go back and forth as much as you want until you decide the story is complete. Make the story take turns in plot and have the characters do all sorts of things, from one paragraph to another.
Join a collaborative story website where writers from around the world create stories together. After signing up you can take part in writing as many stories as you like or even start your own so that others can collaborate with you. (See Resources.)
Create a collaborative novel by writing either part of a chapter or a whole chapter and then alternating that with one or more friends. You can either decide before you begin where you want the story to go or what you want the characters to do or you can just let the story evolve as you go.
Collaborative stories are sometimes called chain stories because of the way writers link their ideas together to create them.