mercurial

obensonne / hg-autosync. An extension for Mercurial that implements automatic syncs between working directories via a central repository. Can be executed manually as a command or in daemon mode (then it simply runs cyclically at intervals). This way you can do something like a controlled Dropbox - only the included files are synchronized. I would prefer a combination of inotify and xmpp Notify instead of the interval solution - this way the daemon would not constantly start up. But something like this could perhaps even be built from it. Update there is already such a thing.

WorkingWithSubversion - Mercurial. Since I keep encountering outdated SVN repositories and clearly prefer Mercurial, I should take a closer look at hgsubversion.

RecordExtension - Mercurial. Great, I hadn't noticed this before. With this, you can select individual patches to commit when you've done several things at once but don't want to commit them together.

vcscommand.vim - CVS/SVN/SVK/git/hg/bzr integration plugin : vim online - something I'd rather do in a shell than in the editor. Mainly because I rarely have single-file commits. But for querying history, it could still be interesting. It's also one of the more active Vim plugins - some of them are really shockingly old, but still work well. One plugin even had a reference to its homepage at GeoCities ...

Amp | Version Control Revolution - Mercurial in Ruby, with a strong focus on extensibility via a Ruby DSL. If I think about how often I use a VCS as a basis for all sorts of things (e.g. automatic deployment of blog postings in one of my blogs), this could actually be pretty cool.