Xsyon, you might want to check out Notorious Games' latest architecture contest. The event runs from February 1st to March 1st, and it's open to both small tribes (between one and five members) and larger groups (six or more members).
Since it's an architecture contest, you'll obviously need to construct (or re-construct) your tribe settlement. Notorious will be judging your creations for originality, uniqueness, design, layout, and beautification.
The dev team is remaining coy when it comes to contest incentives, but the latest Xsyon press release does say that "there will be a large prize for the winning tribe in each group."