The execution engine uses a WebSockets API courtesy of http://codebrew.io, more specifically https://github.com/jedesah/scala-codesheet-api (see http://www.reddit.com/r/programming/comments/1ry70r/hey_this...)

Credits for other open source resources: http://scalatutorials.com/about.html

The tour steps are in a Google docs spreadsheet (lazy man's database) and I wrote a hacky google docs CSV to markdown engine to avoid some boilerplate at: https://github.com/eranation/ScalaTutorialsTourMaker