I once got paid to work on an Open Source (Apache 2.0 licensed) middleware proxy built in java. There is plenty of interesting work on this project. We made use of Akka, Scala, Jetty, and tested it all with Spock.
Is done enough! I used to use Octopress, which is also very well done, but I decided I wanted a bit more flexibility. Perhaps I'll switch back when Octopress is gemified.