There have been rumblings about this for a couple of weeks, but it finally seems set - Ben Stiller is to produce and possibly star in The Return of King Doug, based on an about-to-be-published graphic novel.
The story focuses on the eponymous Doug, a man who has to return to the fantasy world he left behind some 30 years before. So think a little bit Hook, a little bit Neverending Story, and you're probably close - although since the book isn't published yet it's hard to be sure.
Greg Erb and Jason Oremland wrote the graphic novel and are writing the script. Both have experience on film - they're responsible for the upcoming Disney Frog Princess, and also wrote Fraidy Cat (no, not the Tom & Jerry one), which was in development at Disney but appears to have stuck there.
More on this as we get it - on the face of it, it sounds like Stiller could have fun with the concept, but that it risks being more like one of his Night at the Museum-like family-friendly outings rather than one of his, y'know, funny ones.