Hi! I haven't seen anything mentioned here about helping folks who aren't up to speed with Git getting up to speed with Git (couldn't resist). So -
The biggies -
There's some good stuff on here, especially the Book. The Book starts at the beginning, and I can't tell you where it ends, because I just haven't had to get that far with it yet.
Like I said in my introduction, I'm fairly new to development in general so I'm not sure how anything got done before a service like this one. It's fun. There are mountains of cool projects on there, categorized every which way, so if you're looking for something Drupal, well you'll get the point pretty quickly. It's got a pseudo-social-networking component, and it's free for open source projects. This is me.
There are also lots of good resources on there for learning Git as well. Namely learn.github.com.
That should be enough to keep new converts busy for at least a day or two, but there are undoubtedly other resources out there, so let 'er rip.