As we announced quite a while ago we moved all of our plugins to github. Since then, we've moved all of our client work (where we provide the source code repo) to github as well.
We had kept our subversion server online, with nothing being updated on it (all updates were in git), but earlier today we shut it down completely. If, for some reason, you were still using the subversion instance of one of our plugins, you'll want to get it from git now (you would have been using an outdated one anyway).
You can see all of the plugins on the thoughtbot github page, but here are some of the most popular.
While we're on the subject of git and github, I'd like to mention that paperclip is the 18th most watched project on github, while paperclip and shoulda are the 21st and 22nd most forked projects. Congrats to everyone involved in those projects, and thanks for making them successful.