The Abyssal Campaign (DOC). This is a very dark long adventure (or short campaign) almost entirely set in the Abyss. It provides lots of detail on the plane in general and on a number of Abyssal locations. The PCs are trapped in the horrific lower plane by a powerful curse woven by a demon lord, and they have to survive the plane and the fiend's agents before they can find a way to escape. Tough combats, complex moral choices, and a general sense of isolation and loneliness make this adventure unsuited for the faint of heart. The Abyssal Campaign is far from complete, though it already is more than 100 pages long.

The Abyssal Campaign (PDF). The PDF version is usually somewhat behind in updating, due to my lack of a good PDF-making software.

Matter of Opinion. A Planescape adventure where the PCs are chasing a never-heard-before artefact which seems to change its shape and powers to match the beliefs of those surrounding it. Someone has fed false information to a number of factions and power groups about this artefact, causing each of them to desire the item for themselves, and the PCs are in the middle of it all.