A Ding Dong ditch is when you ring somebody's doorbell after placing a foil wrapped Ding Dong on their door mat, and then running away to hide behind the nearest bush. Then you try to not giggle out loud as some old man or lady opens the door, wildly looking around and shouting "Who's there, who's there!" until they notice the foil wrapped Ding Dong sitting on their doormat. For it is then, that they realize that they have been had - another victim of the Ding Dong Ditch.
