I know this would be extra work for someone Clubby, but would it be possible to add a simple list of currently active competitions above the threads in the Competitions forum?
I'm imagining just a simple 2-column, 3-row (or thereabouts) table with the competition name (linking to the forum thread) and the deadline. This table could even be dynamically included on the front page, or given its own page. It could be manually updated by someone. I'd be happy to keep track of the competitions and do this part, or an admin could do it. Just an idea!
To expand on this idea, what if Competitions had their own section of the site where you made a competition page similar to a project page and you put a description and rules and such, and it has a poll sort of thing where you select whethe you are entering, might enter, or won't enter. You can change your answer at any time, and if you choose to enter, you could get notifications on the side bar like with project updates. Or just add a poll to each competition thread and give notifications like that (specialized thread formats).