I've just read a news article on the BBC News website that reminded me that there still are people in the world who want to do spontaneous things just for fun. Apparantly there is a tradition that's grown up in recent years in California which sees thousands of people moon passing trains on a given day each year. The appropriately named Moon Amtrak day was yesterday, July 11th.
The even have a website dedicated to the event
Yeah, and you'd guess for something fun, the authorities are trying to "crack" (sorry couldn't resist the pun) down on it.