There is no Greek life at LSE. In fact, most students probably have no idea what Greek life is. This is because Greek life is an entirely American phenomenon. While fraternities and sororities often run the social scene at American colleges, at the LSE, it is run entirely by the Students' Union. This means that there is no level of exclusivity to the campus party scene. Any student can attend any event.
If there is one group on campus that seems to parallel the idea of a fraternity in the American sense, it is certainly the rugby team. New entrants to the team do have to undergo something that is very similar to the "pledging process." Also, at the Athletics Union party every Wednesday night, the rugby team tends to run the show. They are by far the rowdiest team and in many ways act like the stereotypical "frat guys." The similarities between American fraternities and the LSE rugby team are comical in their simple logic.