A friend of mine sent this link in an email, and I got quite a kick out of it. Of course, there's no way to know for sure, but it appears to me that these people did this purely for fun and enjoyment. To entertain themselves and those around them.
The question most present in my mind as I watched this was that the idea had to have come from one person, who then coordinated the whole thing. It made me wonder how many people my ideas will affect. It's like dropping a pebble in a pond and watching the ripples turn to waves.