Here is an example 5 Room Dungeon to inspire your contest entries. In your campaign, you’ll need to flesh out some of the details, but this skeleton format is perfect for GMs to pick up and customize for their own memorable sessions.
The Dragon Isles consist of no less than thirty or so separate islands, of varying sizes, in a fifty-mile chain running on an approximately north-south line about thirty miles off of the eastern coast.
An evil ruler got the idea of mixing a trampoline and a gallows together. As long as the one to be hanged bounces on the rubber trapdoor it won't open, but bouncing gets very tiring after a while.