Did anyone ever play that game when they were kids where you get a piece of paper and fold it into a zig zag shape with about 3 or 4 folds.. then one person draws the head, another draws the body and someone else eventually draws the feet.. in the end you get this mad looking person. the key being that none of the other people knew what the other drawings looked like, they just had the guidelines for the next part to go from.

I've seen this done with stories too, different people have a chapter to write using only the character's basic information for guidelines.

This sort of thing would be great as a competition where there was one standard engine to use and different people were working on different parts of the game, but in secret.

Everyone just uses placeholder graphics, which are of the same size as the main char.

The level designer doesn't know what the final textures will look like

No-one knows what the music will be

The sound effects could be anything.

Perhaps this sort of competition should be for multiple forums, some sort of inter-community project.

it would make some really mad games though and might accidentally make a classic.

You could get some mad Physics based platform game featuring pandas shooting bananas at skate punks in a post apocalyptic jellybean factory to the tune of ride of the Valkyries..