Okay, here's a new twist on the "never ending story" concept. It might work, it might not - I guess we'll find out soon enough.
The story begins with two characters who are famous celebrities. They can be singers, actors, sports players, anybody who we're all likely to know. The first post begins the story, using those two characters.
The next person to reply gives only the name of one other celebrity. That's it, just the name. End of post. It can be anybody, but again, someone famous we're all likely to have heard of.
Then, the next reply will continue the story, but bringing this new celebrity into the mix somehow. It doesn't matter how, and it doesn't matter if their involvement lasts beyond one post, but they must be written into the story. Characters can be dropped at any time, to avoid overcrowding the plot, and can also be brought back in at a later point if the current writer desires.
The next post after that is, again, just the name of a celebrity, leaving the next person to continue the story whilst bringing this celebrity into the scene.
I hope that explains it well enough. The first person to reply can begin with the opening paragraph of the story, featuring two famous people. Then, the next poster should only give the name of a new celebrity, leaving the third person to add to the original paragraph using this new character.
Now, go!