I have the accounts at:
Rails is moving from Subversion to Git and is adopting Lighthouse for ticket tracking.
I recommend the PeepCode screencast.
Some coo links from the comments:
The git source code control system was developed by Linus Torvalds for managing the Linux kernel. But it’s also valuable for managing all kinds of code: libraries, web applications, personal files.
Git was built for the modern developer’s workflow. Easy branching, full capability even when offline, and fast operation make other source code management systems feel underpowered compared with git!
I really should learn Git. The more I hear about Git, subversion sounds so yesterday.