I remember purposely clogging the gutter storm drains when I was a kid. We did it so the street would flood and we could then break out our "Skim Boards" and surf in the street. I say that because this looks like something we would have done as kids.

This does look like fun but also seems very dangerous. It surprised me that no adults are attempting to stop them. They certainly are having fun though. Kids ... Please don't try this here!