Awesome contest idea John!
Quite possibly my most memorable experience from Halloween (besides that night ALWAYS being mandatory pizza night!) was when I was bout 12 or 13... nearing the end of when it was considered OK to trick-or-treat. It was about 8PM, time for trick-or-treaters to be out. My parents house had a long L-shaped brick-layered sidewalk that led up to the front door which also happened to be within birds of view of one of my favorite climbing trees. As I watched from inside the house as different kids in costumes would approach the front door I noticed that many of them, upon leaving, would head off into the direction of that tree on the way to their next house. I called my buddy upon, and informed him of my plan. We both dressed up in the darkest clothes we had so that no one could see us. Dark jeans. Black long sleeve shirts. I think we even got some of the winter hats out to cover our heads in darkness. We armed ourselves with 2 bottles each of silly string and proceeded to sneak outside and climb up the tree. It was at this point that three girls walked up to my parents front door. Happy with the new goodies they had just received, they headed out towards the tree without a care in the world. Right when they were just at the trunk of the tree my friend and I excecuted the PERFECT NINJA SURPRISE DROP and doused them all with a good volley of silley string. The girls screamed so loudly it was almost like I was at a rock concert my ears rang so loud. They all took off in different directions and dropped their bags of candy in the process. I had never laughed so hard in my life... but was promptly scolded by my father and forced to return the girls candy.
Still makes me smile thinking of that one