Taking a 14-Year Break
The 14 years Cameron spent developing Avatar were brutal, so he's really in need of some time off. Another good 14 years or so should do it. Look for his fighting-cyborg movie Battle Angel Alita to come out in 2046. It will be a documentary.

Starting his Avatar/Titanic Crossover
While Cameron is happy with Avatar's haul so far, he's angry that the film may still not beat the number-one box-office earner of all time: his own Titanic. Recognizing that franchise films tend to do better with each installment, Cameron has begun scripting Titanic Avatar, a crossover about a giant boat full of Avatars that hits an iceberg. It will make a trillion dollars.

Mounting a Legal Defense
Every successful creator -- J.K. Rowling, Stephenie Meyer, Avril Lavigne -- eventually gets accused of stealing their most profitable work from others. Cameron has borrowed from so many sources that it's only a matter of time before a sci-fi author (or their estate) turns up with a long-forgotten novel that bears an uncanny resemblance to Avatar. With a billion dollars at stake, Cameron can't afford to lose any of it. That is, he can, but he doesn't want to.

Telling Everyone 'I Told You So'
While Cameron himself will be on break, representatives will be going door to door, visiting all of the people who expressed doubt about Cameron's sanity, the film's appeal and its ability to make back its money -- and flipping them the bird.

Signing Anything He Can Get His Hands On
After all the negative publicity he got from the circulation of that video of him refusing to sign a fan's Avatar poster, you can bet that Cameron will now sign pretty much everything anyone ever hands to him, ever. Credit card receipts, elementary school permission slips, posters for Piranha II: The Spawning... anything is fair game.

Growing a Real Na'Vi
While doing his research into the science of cloning, Cameron built, in parallel, in his own home, a laboratory where his DNA could be combined with the DNA of frogs and monkeys to create a real Na'Vi that looks vaguely like him. Several custom suits have already been made for it, and once he uploads his brain, his real body will never leave the house again.

What do you think Cameron will do next? Hypothesize below.