Grsync is an open source rsync GUI (Graphical User Interface) which you can use for file and directory synchronization (for backups, etc.). Grsync 1.1.0 was released 2 days ago and it adds some small new features as well as some bugs fixed:

Why would you need this? Let me tell you for what I'm using it: on my work computer, most of the ports are blocked, meaning I cannot use a Bittorrent client. I can, however, use a remote Bittorrent client, and then I use the steps described in this article to synchronize the remote Bittorrent download folder with a local folder.

Grsync is an open source rsync GUI (Graphical User Interface) which works on Windows, Linux and Mac OS X. Rsync is the well-known and powerful command line directory and file synchronization tool.

You can use it for easily data backup alongside Dropbox.

FlyBack is a snapshot-based backup tool based on rsync It creates successive backup directories mirroring the files you wish to backup, but hard-links unchanged files to the previous backup. This prevents wasting disk space while providing you with full access to all your files without any sort of recovery program. If your machine crashes, just move your external drive to your new machine and copy the latest backup using whatever file browser you normally use.