Jiva is hosted on Google Code:
http://code.google.com/p/jiva
Jiva is written in Scala, a very powerful OO/Functional hybrid language that runs on the Java Platform:
http://www.scala-lang.org/
Jiva started out life earlier this year as a GA toolkit written in Java. I decided to port it to Scala because I figured that this might be a good way for me to (a) learn Scala, and (b) have some fun in the process. And I think this has turned out to be mostly true (especially the fun part!).
I should point out that despite its early-release status, Jiva is pretty functional (http://code.google.com/p/jiva
Some quick links:
Download, Build and Run Jiva: http://code.google.com/p/jiva-ng/wiki/JivaQuickStart
Defining and Running GA Problems: http://code.google.com/p/jiva-ng/wiki/DefiningAndRunningGAPr
Samples: http://code.google.com/p/jiva
Other tools used by Jiva:
Sant: for builds (http://code.google.com/p/sant/).
JMock: for testing of Scala code (http://www.jmock.org/).
New Scala Eclipse Plugin (http://lamp.epfl.ch/~mcdirmid/scala.update).
Much4.us: for Backlog/Task Management (http://much4.us/much4/).
Many thanks to the authors of these fine tools! I used them pretty heavily while working on Jiva, and they all held up very well and provided extremely useful functionality.