hell week

noun2

1. •
   (US) The week during which new members are required to undergo undignified rites of initiation or gruelling discipline in order to be accepted into a fraternity, sorority, secret society, military group, etc.

   • She was among a number of cadets taken to the infirmary with heat sickness on the first day of the rigorous drills called hell week. — 1995
2. •
   (US) In a college or university, the week leading up to final examinations.

   • I finished my exam and handed it to the grad assistant at the front row. […] I had finished Hell Week! Winter break has officially begun. — 2002