A prank typically played by children where the prankster knocks on the victim's door or rings their doorbell and runs away thus leaving the victim with no one at their door.
Also the name of an indie pop band based in Waterloo, Ontario who have been together since 2004 and have released two self-produced EPs entitled Hurry! (2005) and Based on a True Story (2006). They have performed at mostly small venues around Southern Ontario and have played the University of Waterloo's Canada Day festival and the Halifax Pop Explosion. There is currently a full length LP in the works right now.
Hey, let's go play knock knock ginger on that kid's house!