Often times, holidays are declared to commemorate a historical event that needs to never be forgotten. For residents of Princeton, New Jersey, one of those historical events involves emptying your bladder. Peeing Day (also called Pissing Day) is a Revolutionary War remembrance that’s more than a little nasty. Apparently, after the American revolutionary troops expelled British general Charles Mawhood from Princeton, they whipped out their free penises and pissed all over his troops. Now, modern Princetonians re-create the Battle on the second Saturday of March, urination and all.