I signed up to the CPAN Pull Request Challenge - apparently I'm entrant 170 of a few hundred.
My assigned dist for January was IO-Digest - this seems a fairly stable module. To get the ball rolling, I fixed the README, but this was somehow unsatisfying. :)
To follow-up, I added Travis-CI support, with a view to validating the other open pull request - but that one looks likely to be a platform-specific problem.
Then I extended the Travis file to generate coverage reports, and separately realised the docs weren't quite fully complete, so fixed this and added a test.
Two of these have already been merged by the author, who was very responsive.
Part of me worries that Github is a centralized, proprietary platform that we now trust most of our software source code to. But activities such as this are surely a good thing - how much harder would it be to co-ordinate 300 volunteers to submit patches in a distributed fashion? I suppose you could do something similar with the list of Debian source packages and metadata about the upstream VCS, say...