Here is another awesome hack. It all began when Skytee saw on the web an Internet-fed air quality data meter that had an old voltmeter for displaying the results. The prototype was the TorrentMeter Mk. 1, with from a custom made voltmeter. Then he got himself a voltmeter dated back in 1908, with brass housing and diameter about 20cm. Using black tee he made a paper look as old as the original scale-paper, and used it to print his own Mbps scale on it.
It is most interesting to read how he acquires the data. He made a Perl-scrip that loops periodically. This script gets the info from the Linux router's /proc, and then tunnels it through the RS232. And there is an Arduino waiting patiently to get these data, which in turn converts it to PWM. A simply transistor circuit then drives the gauge. Check out the documentation for this bandwidth meter.