A yearly Math competition between Williams College and Middlebury College, taking place on a Saturday each fall. Whichever team wins gets to keep an avacado-green chicken-shaped casserole dish ("the Green Chicken") for the next year. The chicken sits on a wooden base with the year and name of the winning team for each year since the contest's inception. At Williams, the Green Chicken is kept on the cookie and juice cart that is rolled in after every math colloquium. The Class of 2007 had the Green Chicken at Williams for their entire time here.
Read more about the team (at least until 2001) at [1]
Current homepage for the Williams team is at [2]