Guerilla Gardening: I just found out about this and well want to give it a go lol! There's several definitions of it. The two that are interesting are the

Carol, what happened here?

I had to look this up. Without a thorough exploration I only found one definition, though. Great idea as long as the land isn't derelict for a reason (toxic).
I have heard the expression 'going guerrila', so maybe this is connected with this outdoor activity. Means liberating yourself from your