Break them down into the most basic categories, or make it a requirement that a post topic must contain that info
like if Grant wants to post a recipe for questions, it has to have All Grain/Extract, Style, and batch size in the title, so its easier to search for what you are looking for as opposed to compiling a database of recipes
Beer Advocate actually does this pretty well under there Beer Styles section, although I would combine a bunch of them in the categories, like throw dry irish stout, oatmeal stout, Russian Imperial Stout, ect into one category called "stouts"
If you want to do a recipe contest, thats going to be hard. That would mean each person would brew each one of the beers and then have a comparison of them.
Or, we could hold monthly competitions, and then have the beers sent out to a couple of people for judging. That would be kind of fun. That way we could judge them, and give legitimate feedback for people, and do like a "Brewdown Crown"