I was thinking about a couple of forum games that could be adapted to help move a language forward.
The first is "Word Association". The first person posts a word (new or previously existing) in the language, and the next person posts a word that the first word brought to mind (along with any notes it might need for usage, etc or with an example sentence, even.) For instance, if the first person posted something that meant "cat", the second person might post a word for dog, or mouse, or fur, or soft, or meow, or graceful, or leap-- wherever their mind goes!
The second thing I had in mind was the "One Sentence Story" game. This is a forum game where each person writes one sentence in turn to advance a story. (It's usually done in a light-hearted, humorous way, but it could be more serious as well.) The first person might post something that means, "It was a dark and stormy night." The next person might post, "Jojo was getting wet because he forgot his umbrella, " and so on. For our purposes, it would probably be good for people to break down their sentence with a literal gloss or interlinear, and a listing of any newly coined vocabulary.
Does it sound like fun? If we can get a few more ideas hammered out in the next week or so, so that we have some useful grammar and a rough idea of what valid words look like, I might like to give this a try, even if people start out using conflicting grammar models. We can't grow toward common usage without using the language, after all.