Curious about the frequency of distributed denial of service (DDOS) attacks? The Digital Attack Map provides an hourly updated map identifying evidence of currently active attacks.
The site uses data sourced from 270 ISPs by Arbor Networks; the site itself was built by Google Ideas. As well as the "live" broadcast, the site also includes archive maps for notable attacks; an attack on Australia in August this year is shown below.
Neither the attackers or the targets are identified, but it's still an interesting source of data.