A week at some fraternities where the pledge class must learn the information on the house they are pledging. Some houses have more than one week they do this throughout the semester of pledgeship. The pledges are usually hazed a little and they learn the house rituals. AKA "R-Week" or "R#" (# is whatever ritual week it is.)
Pledge 1: Did you learn the full names of the house founders and all that other shit yet for R2 tonight?
Pledge 2: No not yet
Pledge 1: Your so fucked dude, i've been studying all week and didn't have all the info memorized til today.