Phi Sigma Kappa

I'm a fourth year and in all my years going to school here I have never heard of Phi Sigma Kappa or their parties except during rush week. I have even heard of parties or met guys in less popular frats like Pi kapp, Asig, Fiji, Sig Pi etc but I have never met a single Phi Sig or heard of any Phi Sig parties. Do these guys even throw down? where do they rank with the other houses at CP?