I made a few myself for convention oneshots that work well. They each consist of an evocative intro paragraph and several leading questions, and sometimes a neat picture.

I'm adding a section about them to Chasing Adventure, and wrote a new one that I'll be using for Dungeon World Day.

You found it! After centuries of rumors and myths, you are the first to lay eyes on the legendary Cloud Fortress. Despite the ancient battle scars covering its surface, the fortress's hull gleams brightly in the sun, its cloak of clouds falling away at your approach. As your hot air balloon softly touches down at the fortress entrance, its edifices begin to pulse with an ominous light.

-What mysterious technology seems to power the fortress (fans, rockets, crystals, etc)?

-What ancient battle did the fortress participate in?

-What terrible foe is it said damaged the fortress long ago?

-What unenviable fate do legends say befell the fortress's inhabitants?

-What powerful weapon did the fortress once make use of?

The important thing for these versions is that the table takes a 5-10 minute break to let the GM prep after character creation and questions being answered.