Grand River II
Grand River Valley II (commonly referenced as to GRV II) is a city-building challenge, and the continuation of an idea first explored on Simtropolis called Grand River Valley. Both challenges were created and handled by the same two people: mrbisonm and lynncanox. This edition is hosted on SimCity 4 Devotion, and is open to anyone with a registered account there. The rules for this competition can be found here, and a list of current (and past) participants can be found here. So far 7 (6 regulars and 1 intermezzo) challenges, for which a synopsis can be found here.
The region, which is used by all participants, was designed by mrbisonm and lynncanox. There is a fictional border separating north and south running along the river. As per the rules of the challenge, there should be some sort of visible difference between the two sides, though what that difference is has been left up to the individual participants.
For several challenges in the early rounds of the game, players were asked to select a side of the border to play and the opposing side was to be governed by another player, selected at random. They would dictate the development of their side of the player's region and it would be the player's job to enact those demands. Part of the challenge is adapting those demands into the ultimate vision for the region.