City Of Ember

Walden Media are to continue their fantasy-book adaptation streak by bringing City of Ember to the big screen. Jeanne DuPrau's post-apocalyptic mystery is the first in a series of three books, with at least a fourth to come, and Walden are, of course, hoping to have a franchise on their hands.

The setting is intriguing - a sealed-off city beneath the world's surface, lit only by articicial light.
In this first story, a time-capsule that gives escape instructions is planted, to open only when it will be safe to return to the world above.

Even more fascinating is the sequel, People of Sparks, that sees the Emberites return to the open space of the planet's surface, meeting the people of a village called Sparks. For her third installment, The Prophet of Yonwood, DuPrau wrote a prequel set in the lead-up to the massive war that drove the people underground. The fourth book is anticpated to be set after Sparks in the chronology, so I can imagine Yonwood getting bypassed or postponed if a series does indeed enter production.

[EDIT: Monster House's Gil Kenan is set to direct. That's great news. Attempts to raise funding/distribution will take place at Cannes]