Each month a CPAN distribution is assigned to you. You have one month to submit at least one pull request.
Which distributions (with github repos) haven't been assigned yet, and their score.
Mailing list: Subscribe via blank email to email@example.com
Things to help with your pull request:
At the moment the 2016 challenge is invite-only, for reasons explained in the announcement.
Hopefully it will eventually be open for all-comers.
CPAN distributions that don't have a github repo, and so won't be assigned in the challenge. Maybe you can help get one of them on github?