Nolan is at that wonderful spot where he can do whatever the hell he wants to, and the executives will let. That's how James Cameron was able to spend a solid decade making ocean documentaries and still get the funding for Avatar. Everyone's been wondering what Nolan will do with his newfound freedom. The two projects he's been rumored to be attached to were a Twilight Zone film and the next James Bond flick. Now, it's been reported that Christopher Nolan is interested in a previous Spielberg time-travel project called Interstellar.
The script for the film is written by Christopher Nolan's brother Jonathan, who wrote both The Dark Knight and The Dark Knight Rises. Very few story details have emerged, but the project is based on the scientific theories of Kip S. Thorne, a physicist who argues that worm-holes do exist in space that can allow one to travel through time. It was actually Steven Spielberg who first heard of the theory and commissioned Jonathan Nolan to write the script.
It's hard to say much when we're given this little information, but Nolan has been good at developing his brother's scripts in the past, so this is something to be optimistic about!