Joshua BishopRoby has an interesting piece up about how to deal with some of the problems that arise during an open-ended game:
For a lot of gamers, “roleplaying game” is synonymous with open-endedness, a developing experience that can go on and on indefinitely, accreting details and significance and personal resonance. While the open-ended nature of roleplaying games does have some distinct advantages, especially in terms of investment and immersion, those advantages come at a cost. Somebody has to keep the flywheel moving, and that is not always the easiest thing to accomplish.
There are some good insights and ideas in there, and it’s worth reading if you’re running (or planning to run) a long-term campaign.