I participated in Scott Kelby's Worldwide Photo Walk this past weekend. Over 30,000 people participated around the world.
A photo walk is a group of photographers getting together in one place, ambling through a town, and photographing anything that moves or doesn't, basically terrorizing the natives. You discuss equipment, techniques, composition or anything you can get them to talk about. Just watching what they photograph is a learning experience. I wholeheartedly endorse this annual event.
View images from the walk that I posted on Flickr here.
View the San Francisco North Beach Walk group photos here.
And view walk photos from around the world here.