Following a discussion we had on the site, I thought we could start up a thread to post the pre- and post-apocalyptic effects of a comet/minor planetary impact on a campaign world.

The Great Gate of Calast is not like other gates. It's got a mind of its own...

Two sly-looking men turn up in town accompanied by a third man who says very little and who they don't allow to be seen much.

A transcription, beyng the seminal introduction by Mr S J Ponsuler to the theory and praxis of Dracapodemy, the studie of Dragons' migration patterns. This tome ys to be founde in the librarie of Anserne University, alonge with many years of copies of the Dracapodemyst's Almanac not to mention verious othere tomes on the subjecte.

(Another submission I'm transferring over to the main site from the fora).

When wizards go mad, what curious ruins do they leave behind?

To give a world a feeling of otherworldliness, it is best to replace some standard, everyday objects by imaginitive replacements. I thought I'd turn to musical instruments as music often defines (or embodies) a culture.

This is just a first idea, feel free to post some more, because I will...

This looks like an elaborately fashioned wooden egg-cup, but it is a powerful magical tool, used mainly by witches to conjure up spirits and familiars.

Carmo keeps a shop in the backstreets of Erezi. It's not often visited, Carmo makes people feel...uneasy. Even the veterans of the Erezi underworld are uncomfortable being alone with Carmo. But they need to buy their traps from somewhere...

The characters are stranded on an island, where a wizard, corrupted by the powers of the first Blue Book, has been killed by his own magical experiments. They will discover the awful truth that lurks in his subterranean workshop, and a seed of evil will be sown...

The Despotic Queen of Shiant has decreed that a competition will take place in the month of Oconerry. She will have built a labyrinth through which the contenders must pass in order to win the ultimate prize: her hand in marriage.

An impressive citadel in the Askharnn mountains. Their prohibitive laws on travel during the Winter months can be a problem for pilgrims and wanderers.

Although it can be a distraction, it can also add atmosphere to an adventure to have music playing in the background. Here are some pieces I'd recommend for different situations.

In the darkness in the south transept of the Cathedral of Isielles stands the resplendent Clock of Shadows. It tells more than just the time of day...

Unknown to anyone, a glamorous ball for the Duke of Erezi will turn into a confusing and chaotic bloodbath.

The mystery of fyre is one which has much occupyed my studies and the studies of men before me. ... I have concluded that fyre is the product of Fyre Antes.

Professor J Klewlise, "On the nature and origin of fyre" (1542)

I don't know if I posted about it before, but I have always wanted to run an adventure set in a library. The following is a sketch of an unusual premise and a possible plot-hook.

The grisly anthropomorphisation of a rockfall...

A dangerous book of maps...

An icky sideline plot to a forest adventure.

A (fairly sketchy) outline of a one-off adventure I ran based around the (time-honoured/hackneyed) Tunguska Event of 1908. As such it is quite specific (hopefully not hackneyed) and will probably best serve as a specimen for dissection to get those parts you can use in your own adventures. But then this is an Ideas Guild after all...