Feathered flash-mob stages pillow fight in San Francisco

San Francisco's Justin Herman Plaza took on the look of a massive sleepover last night, as hundreds gathered, armed with pillows, for what would be the latest Facebook-fueled flash-mob event to capture media attention.

The massive pillow fight is an annual event in that city, now in its sixth year, but the event has no official organizers, which puts the only negative spin on what seems like an otherwise fun moment. With no organizer, the taxpayer is on the hook for cleanup costs, which reportedly run about $17,500 every year.