I think that the contest we have is a great idea, and I have heard positive reactions from other users too. But except for cheese week, there doesn't seem to be much participation. And I suspect that part of the reason is that most users don't know the contest exists.
Currently, there are two official ways to know about the contest: The meta question announcing it, and the community ad. But when a user surfs with an adblocker, the community ad is not shown, there is an invitation to subscribe to the site newsletter in its place. As for the meta question: not many people read meta.
The inofficial way to know it is to be in chat when somebody mentions the contest. But there is almost nobody in chat except for the regulars, and the transcripts are so long and rambling and offtopic that I can't imagine anybody reading them for informational purposes.
I tried to include a new channel of information: I asked a question which was so broad as to go unpleasantly close to a poll, in the hope that it will elicit the "I have an opinion too" reaction, and mentioned in a comment that it is written for a contest. I don't know if it helped or not, but at least it was answered by non-regulars, so maybe it attracted views from the people we want to target. Still, the method has its drawbacks. First, it is maybe still not visible enough, and second, there is the ethical problem of asking contrived questions once I am eligible for a prize again.
Does anybody have ideas how we can promote the contest better?