At the Wikimania Developer Days this week, several developers led a workshop for MediaWiki beginners, and a code review training covering our coding standards. First-draft notes for both are up:
http://www.mediawiki.org/wiki/How_to_become_a_MediaWiki_hacker/Workshop
http://www.mediawiki.org/wiki/Code_review_management/Aug_2011_training
and I intend on improving them into a more productized curriculum for future hackathons.
Thanks to Guillaume Paumier and to Waldir Pimenta for many of those notes, to Roan Kattouw, Timo Tijhof, Andrew Garrett, Brion Vibber, Tim Starling, Brandon Harris, and other developers for teaching, to Amir Aharoni for initiating the idea of the beginners' workshop, and to Florian Hackenberger for volunteering to have Tim Starling review his code live & onstage.