This a pressure plate switch to set off these cheap little skull things from Wal mart. they were made to be path markers and came with spikes to stick into the ground but I wanted to use them as porch decorations. I extended the wires with some old speaker wire so i could hang them around, and used the "try me" switch that was in the cardboard box as the switch to activate them. It worked well and survived the 70-100 kids we get every year.
Step 1: Just a small scrap of particle board
Step 2: The underside
Just make sure none of the screws are long enough to protrude through the board, even if its stomped on and broken.
Step 3: The "try me" switch from the box these came in
I drilled a hole in the little foam backer thing that the switch was stuck to, and screwed it in to the side of the center board, mine worked on the first shot just by eyeballing it so I dont know how fussy you would have to be with the position of it.
Step 4: Where the switch plugs in
Step 5: Additional Photos
Just make sure when you extend the wires you keep the polarity the same, the LED's wont work if the wires are reversed, they are diodes after all.