Time for the one sentence of info on the Adventure Time film. Cartoon Network is working with Warner Bros to make a Adventure Time movie , produced by Chris McKay and Roy Lee, from the Lego Movie. Wow Warner Bros, way to do something good again. You had the Lego Movie and know this, so like two things. There are no other details online at this time, everything else will be an article with worthless facts you already know if you're a fan.
Update: Here's a good example of a post on the film just arguing if it's too late for a film to be popular when it's release,
The "Adventure Time" Film May Be Too Little, Too Late
It has no new information, just speculation from the writer based on Cartoon Network's very shoddy history of releases an overall crappy handling of everything it does.
Will of course update you with more info comes in.