100 Days Ball: Each spring, when 100 days are left at Holy Cross for the graduating Senior Class, the Purple Key Society (PKS), a service organization which fosters school spirit, loyalty, and enthusiasm, sponsors an informal dinner and dance in their honor. Tradition holds that attendees make a list of fellow seniors they would like to kiss, and attempt to follow through before the night is over. Purple Pride Day: Each year, the Purple Key Society chooses a day to banner the campus in the color purple, the official school color, to foster school spirit and pride.