The house system is the basis of undergraduate student residence at the California Institute of Technology (Caltech). Caltech's unique house system is modeled after the residential college system of Oxford and Cambridge in England, although the houses are probably more similar in size and character to the Yale University residential colleges and Harvard University house system. Like a residential college, a house embodies two closely connected concepts: it serves as both a physical building where a majority of its members reside and as the center of social activity for its members. The houses resemble fraternities at other American universities in the shared loyalties they engender. Unlike in fraternities, however, potentially dangerous "rushing" or "pledging" is replaced with two weeks of "Rotation" at the beginning of a student's freshman year, and students generally remain affiliated with one house for the duration of their undergraduate studies. Freshmen have historically gone through a process known as Rotation for a week before term through the first week of classes, leading to their eventual house assignment by way of a matching process. This process has rules associated with it to try to give freshmen a chance to choose among the houses in an unbiased way. History Caltech established the house system in 1931, disbanding the existing fraternities and recasting them as Blacker House, Dabney House, Fleming House and Ricketts House, located in the complex known as the student houses, then old houses, and later south houses. The fraternities were as follows: Blacker: Phi Alpha Rho, also known as Pharo Dabney: Gamma Sigma Fleming: Sigma Alpha Pi and Pi Alpha Tau Ricketts: Kappa Gamma, also known as Gnome Expanding student population was accommodated in 1960 with the new houses, or north houses: Lloyd House, Page House, and Ruddock House. A new state-of-the-art residential facility named Avery House, was opened in 1996, touted as a facility that allowed undergraduate students, graduate students and faculty to not only mingle, but live together. As a result, Avery was not initially considered part of the house system, and freshmen were not allowed to live there. In the 2003–2004 school year, the Avery Council (the student government of Avery House) campaigned for Avery to participate in Rotation and take freshmen. This change was opposed by the Caltech undergraduate student body by a five-to-one margin, but the Faculty Board voted overwhelmingly to approve the change. Beginning in the 2005–2006 school year, freshmen