Last night was the jump into Mirror Lake by Ohio State students, the tradition that takes place the Thursday night before the Michigan game.
But what exactly were students jumping into?
Students from the College of Earth Sciences tested the water last year before, during and after thousands had taken the plunge.
What they found was a lake-wide temperature increase of approximately 3 degrees during the course of the night. They also found a spike in ammonia. That means urine.
"It went from a background of 5.2 parts per million to a peak of about 42 parts per million," Steve Goldsmith, a postdoctoral research associate, told the Columbus Dispatch. "So it was an eightfold increase."Goldsmith's advice: "Have fun, but don't open your mouth."