As many have already mentioned, they function just as other groups do. They're generally a good group of guys, though some chapters give more of the Tri-Lam feel (from revenge of the nerds) than others
Just because they don't have greek letters does not mean they do not have a rich fraternal history.
At the University of Oklahoma they participate in IFC rush and also have events with Alpha Sigma Kappa - Women in Technical Studies, and we enjoy having them around.