Everyday I walk to work, usually along the same streets. Recently I noticed a sign spray-painted onto the sidewalk. Now to the casual observer it may not be noticed at all or appear to be a rudimentary house-shape. But to someone who is keenly aware of what threat Zombies pose in today's day and age it is clearly an indication of a nearby safe house!
Now I have two projects. One, document the safe house sign. Two, find that safe house so that when the Zombie horde hits my city. Always be prepared, because duck-and-cover won't help you here!