First install the required gems:
gem install octokit awesomeprint rainbow
Then run it to extract all of your open GitHub issues into files (with comments).
ruby my-gh-issues.rb
Take a look at the issue directory for all issues. Pass specific repositories to only pull those issues.
ruby my-gh-issues.rb cancan railscasts
Note, you may get a 403 error if you have a lot of issues. I'm guessing this is because GitHub is throttling how many requests you can send. Just run the script again and it will skip over the already pulled issues.
Special thanks to the creator of this original gist and the authors of the gems.