Ask HN: Which license for an open-source sci-fi book?

I'm writing an epic sci-fi novel. Well, I hope it will become epic. I have the whole plot and an ending (and possible ideas for sequel) and I wrote a large chunk of the first chapter so far. I'm not a native English speaker, and I'd like to encourage others to chip in with editing or writing new parts of the storyline I have not envisioned yet, by making the book open source. My main goal is to sit in a theater one day and see a blockbuster movie made out of this story. Because I love blockbuster sci-fi movies, and quality ones are in short supply. I assume that studios would only make a movie if they can secure exclusive rights to the material. To sum all this up, an open source license is needed that: 1. would allow anyone to read it for free 2. would allow anyone to contribute to make it a great sci-fi story 3. would allow me to sell the story (for, say $1) to the studio we as a community deem best equipped to create a great movie 4. would prevent other studios from doing the same The closest I could find would be to use Creative Commons Attribution-NonCommercial-ShareAlike. But if there will be many contributors, we could face problems with item 3. above. I'm thinking maybe I should require all the contributors to assign the copyright for their contributions to me, so that I could sell the commercial rights to a studio at some point. Similar to the way GNU works, IIRC. Any ideas?