From @shshaw:
A "live" aspect of the challenges could be helpful. Publicize when the challenge details will be released, then start a live stream 4 hours and 30 minutes after the release to review some of the first submissions.
This is a really fun idea if we can figure out how to manage the extra overhead.
Could also add a badge upgrade / bonus badge (#41) for "did it live", which would be fun.
Needs a little more thinking about logistics, but I love the idea in general.