The Caltech Cannon
Apparently Caltech was having trouble attracting cool enough students. During the 2005 MIT Campus Preview Weekend—when all the admitted students are invited to come sample life at MIT before making their decision—a group of California Institute of Technology students came to the MIT campus and pulled a few minor hacks of their own advertising Caltech as the purportedly-superior school. This demanded retaliation by MIT.
The morning of the first day of the next Campus Preview Weekend (2006), a large cannon appeared in front of MIT's Green Building (Building 54). There was an aluminum plaque bolted to a concrete pedestal in front of it explaining the significance of this new piece of sculpture on the MIT campus:
"CALTECH CANNON. April 6, 2006. MIT hackers posing as the Howe & Ser Moving Company appropriated this cannon on March 28, 2006. It later appeared on MIT's campus with the addition of a large brass rat made of gold-plated aluminum. In honor of its previous owners, the cannon points towards Pasadena, CA."