Skip Day
Senior Skip Day is a tradition in some American high schools where (nearly) the entire senior class will absent themselves from school on a pre-determined day. The skip day is normally picked close to graduation to give senior students a "day off" prior to entering the periods of final examinations. It is sometimes followed or preceeded by a "Senior Prank", where the members of the student class will play a trick or prank on the school administration.
School administration reactions can vary greatly in response to Senior Skip Day. Some schools openly encourage the practive, helping the students pick a day to take off and advising teacher's not to schedule quizs or exams on the given skip day. Other schools, however, may severely punish students for willfully being absent from school to the extent of assigning detention or even going so far as to provide a failing grade or withdrawing a college recommendation.
The origin of Senior Skip Day is unclear, but eh practice has been in effect since at least the 1970s. The film Ferris Beuller's Day Off was a catalyst for several Senior Skip Days in 1980s and mid 1990s.