Here's an idea inspired by xkcd.
How about a "map of the cartographers guild" challenge. What do I mean? Take a look at the link and imagine:
You could have a world map with the continent of bitmap to the east and the vector continent on in the west. On the continent of bitmap rages a great war between the Kingdom of Gimp and the great Photoshop Empire.
On the opposing continent there's the Profantasy Legue, led by the Kingdom of Campain Cartographer with it's vassals the city state of City Designer and the undeground realm of Dungeon Designer.
Down in the south are the mysterious VTT islands basking in the tropical sun. The Worldbuilding Ocean divides the world but far to the south lies the uncharted Sea of Commissions where untold fortunes can be made.
You can make a lot of wonderful details in there. The great Layer Mask River running throug the bitmap continent, the Symbol Set Mountains, the forrest of realism, the labeling islands...
You get the drift...

Challenge or not? Discuss and vote.