I'm not sure about any specific event as much as there are these folks who are all just spontaneously cleaning up their smoke spots and then posting pictures of it on reddit in /r/trees. But frankly, this got so big and popular, we should band together and tackle some larger projects: bring some music and good food and drink and we can have ourselves a great cleaning work party! :)
Wow, thanks for sharing! Is this available all over the US? Feel free to post individual events for the initiative in our "events" room. Thank you again, what a cool thing!