Expedition to the Demonweb Pits

As described on Wizard's web site:


 * A D&D super-adventure that can be played as a mini-campaign or a series of small side adventures.


 * Expedition to the Demonweb Pits is a D&D super-adventure for characters of levels 9–12. It is usable as a mini-campaign on its own, as a story arc in a Dungeon Master’s regular campaign, or as a series of small side adventures with a big payoff. The structure is very flexible and eminently customizable. The adventure uses a new combat encounter format designed to make the DM’s job easier and to speed up play.


 * Heroes who become entangled in the adventure’s plot soon find themselves squaring off against the agents of Lolth and Graz’zt across several planes, including the Abyss.