One of Apple's claim to fame with their Mac OS X version 5, aka Leopard, is time machine. The back-up tool that is so easy to use that your grandmother can use it. Personally, it is one of the simplest way to have your data backed up and make sure that it is done automatically and in the background. Being both Unix-based, Linux can practically achieve what Apple did with Time Machine using the free tools available. This is exactly what happened with FlyBack, a simple GUI-wrapper to the common tools readily available in Linux that allows you to have the same functionality as Mac OS X's Time Machine.
Installing is relatively easy. As indicated on its webpage, you simple get the following tools: python, python-glade2, python-gnome2, python-gnome2-extras, python-gtk2, python-gconf, python-gobject and rsync (if you are using Ubuntu) from your favorite repository and then get the Python script from the FlyBack site and run it.
Now, I cannot wait to see the OpenGL-based GUI for FlyBack.