City on the gyre or dreams
That was my campaign!
I don't have the time to try it again. It really stumbled as players vanished. If someone were to take up the mantle I can provide notes and material, though.
The intention was to create a campaign where low level inexperienced characters had to deal with the bizarreness of the outer planes. The Gyre Of Dreams was a place where leftover pieces of magical demi-planes and chunks of reality drifted in orbits around "suns" powered by the dreams of mortals.
The reason for that was to have an environment that was subject to frequent change and time constraints, due to the "chunks" drifting relative to each other, without having the players use a "go anywhere" power. Being low level, they would want to explore near to home, but exactly what was near home would be subject to change.
The characters had visited the "Floating Forest", inspired by a tropical forest with such a thick layer of roots on the surface that I thought maybe it wouldn't even need ground beneath it. So that's what it was- just forest, mass of roots (with trapped debris, fallen leaves, etc)... and nothing below. The trees had adapted to the environment. The long roots hanging down from the bottom absorbed the energy of the plane. As a result of this visit, they might have future food issues, but they had acquired Chocolate.
I was planning on having chocolate become a highly sought after tradable commodity at some point, popular with all kinds of planar creatures. This would be a sort of chocolate inside joke- the scientific name of the Genus of the Cacao tree is "Theobroma". This can be translated as "Drink of the Gods".