One example is Composer with its "Easy Pick" tag: https://github.com/composer/composer/issues?labels=Easy+Pick...

I think this approach is much better than a generic "I want to contribute" button. Puts the burden on the newbie.

Maybe there should be a standard tag? Similiar to versioning http://semver.org/

Really? I don't think I've seen that before, but that sounds perfect for me. Do you have any advice on how to find such issues?

Some projects that have gone through the GSoC process have triaged bugs/features like this. I'm trying to remember them now - blame Monday.

http://fedoraproject.org/join-fedora is pretty much the best "How to Contribute" example I've seen.

Thank you!