Tomorrow is June 6, 2006; the date 6/6/06 (augh!) won't occur again for another 100 years. How to celebrate? In lieu of animal sacrifices or some other such nastiness, I recommed you kick back with a bottle of Duvel (translation: Devil), Old Nick, or Hop Devil.
Oh, and I almost forgot: Canfield recommends observing the day this way, although it has nothing to do with beer: http://www.nationaldayofslayer.org/