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.
Under the sewers of a large town ancient burial chambers are discovered. If the PCs investigate they fill find that a pale white flowers grows amongst the graves, in the dark.
How do they survive without light? What is their origin? Why in a burial chamber and not just in any old cave?
Can they be sold or do they have any special quality at all? It is up to the PCs to discover.