For my part, at my alma mater, "licensed mayhem" (I love that turn of phrase, mav) was confined to Blue Monday every spring.
It's a little more complex than that, being that it was the final stroke in an inter-class competition wherein bets were paid off and the losing class was relegated to walking the Mill Stream. The preceding week was called Glee Week, Glee being a tradition specific to my university - teams representing each class year would write and perform a song based on a theme, culminating in the inter-class competition on Friday night. Seniors had the opportunity to lampoon the events of the school year in Senior Skits, and seniors also wore beanies (traditionally the purview of freshmen, but it's not classified as hazing if a class is wearing them willfully).
Kind of a quirky tradition of the school I went to, and realistically the mayhem lasted all of Glee Week and through Blue Monday - but Blue Monday was the only *condoned* expression of said mayhem.
Never heard the term
Rag Week until you mentioned it!
