What Are They?
A "zombie walk" is a type of event, usually large-scale. It occurs when a big group of people basically dress up as zombies (complete with costumes, makeup, and other special effects), and march in public -- usually with a specific destination in mind. Participants in a zombie walk must remain in character -- limping, stumbling, moaning and groaning, and often times calling for "brains!" or pretending to cannibalize others.
Who, When and Where?
Zombie walks have been occurring in major metropolitan areas since 2001, the more successful ones occurring in cities such as Sacramento, Toronto, Vancouver, and Pittsburgh, to name a few. In 2007, the people of Pittsburgh set a new Guinness World Record for the largest zombie walk with 1100 participants. The zombies typically march in mobs along a planned route through public areas -- often times ending at cemeteries. Another common site for zombie walks are major shopping malls -- reminiscent of Dawn of the Dead.
Often times, zombie walks are charity events -- either to raise awareness or collect money or goods for a cause. (One such event occurred in 2006 at the Monroeville Mall in Pittsburgh, which collected food for the Greater Pittsburgh Community Food Bank.) Some zombie walks, though, may serve as promotions for other events, or may be just for fun.