Hell Week Meaning

(chiefly US, idiomatic) 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.

Example: 1995 Sep. 10, "Citadel's First Female Cadet Tells of the Stress of Her Court Fight," New York Times (retrieved 14 June 2011)
  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.