SparkleShare is a file sharing and collaboration tool inspired by Dropbox.

SparkleShare isn't just a piece of software, it's part of your workflow.
It's designed to make sharing documents and collaboration easier,
and to make peers aware of what you are doing. It allows you to instantly
sync with any Git repository you have access to. The user interface and
features are made to support this goal.

Though SparkleShare is not made to be a graphical frontend for git or a
backup tool, it may be useful for other kinds of purposes as well, like
backing up small files or monitoring your favourite project.