There are a lot of challenges on the MNFF forums on a frequent basis. But these challenges, more often than not, are judged extremely late, and the results are posted even later. I am not a person who expects moderators to be super-fast, but sometimes, it is disappointing to submit an entry to a challenge where you won't even know the results.
What I suggest instead is a dedicated panel of MNFFers who would be able to judge the challenges that are issued. Something similar to what we have in the QSQs. This way, the moderators won't have to bear the additional burden of judging challenges as well.
Or maybe, we could have two or three moderators who only issue challenges, moderate them as well as judge. Frankly, moderating the stories on the archives, minding the forums, and judging as well as issuing challenges seems to be a really huge task, and the mods are overworked. Division of the work is so much more easier, in my opinion.