In northern New Jersey and the Philadelphia region , October 30 is referred to as `` Mischief Night , '' where mischievous teens soap car windows , egg houses , adorn trees with toilet paper , and run away after ringing doorbells . In South Jersey and the Philadelphia region ( as well as Westchester County , NY and Fairfield County , CT ) , October 30 is referred to as `` Mischief Night , '' where mischievous teens rub soap bars on car windows , throw eggs at houses , adorn trees with toilet paper , and run away after ringing doorbells .