Bob Hearn writes "Some Slashdotters might remember the story Caltech Pranks MIT's Prefrosh Weekend from a year ago. MIT Hackers have gotten even. Sometime in the middle of the night, Caltech's famous cannon appeared at the base of MIT's Green building. A plaque in front of it reads: '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 Padadena, CA.' The brass rat (MIT ring) is really a rather impressive bit of aluminum machining. Harvey Mudd College previously stole the cannon, in 1986, but later had to give it back."