This is quite simple. Just post a few sentences and have the next person make a few sentences that makes it seem like a story.
EXAMPLE: Person 1: The ninjas are coming... Person 2: Some say they have always been here, hiding in the shadows... Person 3: The time they come out of the shadows is unknown.
And it goes on forever. After we get alot of posts I might make this into a RPG.
But sadly, the king died 3 days ago, because the large dragon that lived in the Forbidden Mountains came down and ate him up, so the peasants are free of tax.