Harvard and Yale have been rivals since 1875.
Sometimes the students meet in other ways, such as in this prank, where Harvard students in the comedy group On Harvard Time decided to crash the Yale campus suited up in Yale garb and gave unsanctioned school tours to prospective students and their parents.
Subtle tour-guide hilarity ensues.
Harvard Tours Yale
Harvard Pranks Yale With Hilarious Fake Admissions Tour, Forbes>>