The idea: you add one sentence to the story, and then you have to wait for someone else to add a sentence before you add the next one.
Example:
user one: He turned and walked heroically into the sunset.
user two: Unfortunately he was in a play and the sunset was a background painting.
user three: He rebounded from the backdrop and fell into the orchestra pit, wedging his head into a tuba.
user one: Luckily they were able to get him out by prying on his neck with some flutes and opening the spit valve which equalized the pressure.
user four: However in pulling free of the tuba he fell backwards ......etc.
Now the first sentence:
I was walking down the street when suddenly I spotted something in the distance.
Example:
user one: He turned and walked heroically into the sunset.
user two: Unfortunately he was in a play and the sunset was a background painting.
user three: He rebounded from the backdrop and fell into the orchestra pit, wedging his head into a tuba.
user one: Luckily they were able to get him out by prying on his neck with some flutes and opening the spit valve which equalized the pressure.
user four: However in pulling free of the tuba he fell backwards ......etc.
Now the first sentence:
I was walking down the street when suddenly I spotted something in the distance.