Balloon is an alternative to DropBox with file version control. It is based on Mercurial and supports Git. Local repositories on different hosts are automatically synchronized with a remote repository thanks to the inotify API.
emacs-epackage is an Emacs extension for the Distributed Emacs Lisp Package System (DELPS). With it, you can install Emacs extensions that have been made available as Git DVCS repositories. This format is called "epackage".