Everything I know about Dragon Day I learned from Wikipedia. But here is a little history lesson of the tradition. It started in 1901 and occurs the Friday before Spring Break. The first-year architecture students build a dragon and it is paraded through the arts quad on campus. In the 1980s, the College of Engineering started having issues with the architects and in order to resolve this peacefully, they started building a phoenix each year to meet the dragon on campus.
From my point of view, the phoenix was way cooler. The dragon looked unfinished! But the hoards of people following the dragon were dressed really funny and yelling weird things so that was entertaining. Traditions like this make me laugh. Good ole Cornell.