Mainiac1957 usually sponsors an annual spring CITO event, taking part in the annual Brewer/Bangor River Cleanup Day.
Other than that, I know GCM.org members have hosted CITO events, but not sure if they have been in conjunction with CITO Day.
Wasn't there a big event at the Eartha in Yarmouth? I wasn't there, and I don't remember whether it had to do with CITO day or not; I think it did...
"Given a chance, a child will bring the confusion of the world to the woods, wash it in the creek, turn it over to see what lives on the unseen side of that confusion." --Richard Louv, Last Child in the Woods