A (non-geeky) friend who spent a year at Wellesley used to go along to International Student events on occasion, partly because they were geared towards people who were about out of traditional term time. She met a wide range of people and (most of them) were lovely. Some of the American students who were helping/'befriending' were a bit earnest (at least the ones I met when I visited her) but she made some firm friends. I second the idea of a geeky t-shirt/badge though.