Unrelated to the movie chat idea: A couple friends and I just finished writing a screenplay together where each of us took turns writing one page. Meaning I wrote a page, sent it to the next person, he wrote the next page, sent it to the third, then he wrote a page and sent it back to me, repeat. Our rule was no one was allowed to talk about where it was going at all. It ended up being pretty fun because we kept trying to out-do eachother and/or write the next guy into a hole he couldn't get out of. Maybe we could do something like that here on a larger scale?