The WWFM idea was started in 2007 after 2 cachers attended a mega-event. It was meant to be a fun “opposite” of a mega-event: all the cool aspects of a geocaching event, crammed into 15 minutes of excitement. An added dimension is represented by the letters "WW" - World Wide - these events occur across the planet on the same day at (mostly) the same time! These caching events are intended to bring geocachers together in a creative way, as well as introduce others (newbies) to the hobby.

Check out the History of the Geocaching WWFM events.

Read more about (non-geocaching) Flash Mobs on Wikipedia.

Watch some elaborate Flash Mobs on YouTube.

Basic Requirements:

Hold the event on the official, announced day, preferably at the official time
The event should last only 15 minutes (some locations hold separate "after" events for more fun)
Take a group picture
Collect the number of people attended for statistical purposes
Be creative and Have fun!