The Freebox Revolution has a nice management GUI which provides metrics about in/out traffic. Unfortunately, it can only be seen from the management pages when you’ve been authenticated.
Here’s a way to script the grab of the traffic pictures to show them in any Web page.
I’m (once again) in an RRDtool coding time and I found this (dead?) blog, full of really nice explanations and examples on how to enlighten your RRDtool graphs. I’m actually using the information to render my Xymon metrics in a better way.
Be sure to read the Circles of Archimedes for pretty stylish graphs!