Last year, I had found a site that had an application (either Java or Flash, I can't remember) that displayed an interactive graph of the ASes in the backbone of the Internet. You could select any AS and see in graph form which were its peers, along with a lot of other information, including the announcements received in the last 2-3 days.
For every AS, you could get its whois information, and the prefixes that it was announcing. Everything was interactive.
It was a fantastic visualization and demonstration tool that I showed to my students (Computer Networks course), in order for them to have a glance at how the Internet looks like in its core, how BGP routing was working to keep our packets flowing, etc.
Unfortunately, I can't seem to find this link anymore, and I would like to show it again this year to my students. I would like to know any information about this site, or any other sites that provide good interactive and interesting visualizations about the inner workings of the Internet.