The
military academies in
America spend the entire
summer prior to a new student's
freshman year
indoctrinating them. Other military schools, however, like
Virginia Military Institute or the
Corps of Cadets option at
Virginia Tech, don't have the whole summer to pull it off.
So, they spend one intense week prior to the start of classes attempting to scare off the uncommitted, drive them to physical and mental exhaustion, and instill discipline. This is called Hell Week, in which the new freshmen (usually called something degrading, like rats or knobs), get their heads handed to them.
Rumor has it that if you can survive Hell Week, you can survive the freshman year, and if you can survive freshman year, you can survive your time there. Me, I'm glad I'm a civilian.