September 12th, 2007, Led Zeppelin announced a tribute show to the late president of Atlantic Records Ahmet Ertegun.
The show was to happen at London's O-2 Arena on November 26th, but moved to December 10th because Jimmy Page had broken his finger.
Online registration resulted in over a million people trying to get a ticket.

From that concert, here's Led Zeppelin performing an awesome version of 'Kashmir."