Finals Week
On college campus', during the week of finals, the dorms have set "quiet hours" so that people can study without being disturbed. Tradition has it that on the last night of finals at 12:00am everyone opens their windows and screams for exactly one minute.
On most campuses you can hear someone tell the story that one year, between 12:00 and 12:01am, a girl was brutally raped and murdered and no one heard her scream for help because of the traditional racket put on by the rest of the student body.
Now, according to the story, any one who screams during finals week will be expelled from the school.