From the website:
Participate in the re-creation of the most difficult Waldo puzzle ever! Come out to the square across from the San Francisco Ferry Building on Saturday November 11th at noon in a red and white striped shirt and blue pants. This event will occur rain or shine. If it rains, we will congregate inside the Ferry Building.
Ah, it's supposed to be today. I'm curious how many people show up in the first Mob of Waldos ever!
http://waldo.castlepeakstudios.com/ | Flickr pool (includes how to make your own Waldo customes!) - via Craftzine