Amp: A Revolution in Source Version Control (in Ruby!)
Amp is a new Ruby based project that aims to "change the way we approach VCS" (version control systems). Currently it's basically a port of the Mercurial version control system - a common alternative to the Git system that's more popular in Rubyland - but it aims to abstract things to the point where it could be used in place of Git, Bazaar, SVN, CVS, Darcs, and so forth.
The creators of Amp believe that while there are lots of great repository formats out there, none of the official clients are "truly good software" and so they're aiming to build something that abstracts away all of the pain into a heavily customizable Ruby library and client. Even now you can add your own commands to Amp or adjust those that already exist, meaning you can totally customize a powerful source control tool to your own taste.
One of the points that's constantly stressed on Amp's rather well designed official site is that the project is actively looking for new contributors and help. They have a repo on GitHub if you want to fork and issue pull requests, as well as an IRC channel on Freenode, #amp.