This is great! Back when my parents had a pretty substantial backyard garden, my brothers and I would set up forts towards the end of the summer (made out of whatever we could find...the cage thingys that hold tomato plants up, old boards, etc) and have tomato fights with the last of the tomatoes that didn't get eaten or rotten or whatever.
One year my grandma called the local paper and dude came out and took pics and there was a small human-interest write-up. That year my older brother had donned a bunch of camouflage clothes, hat and everything...and the picture is of him in the middle of a throw, arm back. He told the reporter that in the off-season we threw around cans of Prego to keep in shape.
When I heard of this tradition in Spain I was thrilled; I just thought we were being all redneck.
