The Wiki Education Foundation course system — https://github.com/WikiEducationFoundation/WikiEduDashboard, and live on http://dashboard.wikiedu.org — is also potentially a very useful platform for all kinds of editing-focused outreach projects (edit-a-thons, etc). During the hackathon, we'll be sprinting toward the first major milestone of making this system available beyond wikiedu.org: getting an instance of it up and running on wmflabs, and localizing it for non-Wiki Ed efforts.
The project is built on the Ruby on Rails framework, and uses React.js for much of the frontend. It also interacts heavily with external services: the Wikipedia API, a custom PHP endpoint on wmflabs that provides access to data from the replica database, and stats.grok.se for pageview data. Skills in JavaScript, Ruby, and/or experience with internationalization will be most useful.