Internet Systems Consortium using Drupal
Internet Systems Consortium, also known as ISC, is using Drupal on their website at http://isc.org. ISC was founded by three internet pioneers Rick Adams, Carl Malamud and Paul Vixie to support BIND and other software that helps power the internet. ISC also operates one of the 13 root name servers. Pretty cool and a testament to Drupal!
— Dries Buytaert