how do i make friends outside of greek life

I love my sorority but my close friends are only in Greek life and I don't think this is good considering Greek life only represents 10% of the student population and I really want to branch out. My floor is nice but socially very different than me and the same with my roommates. I'm in several other clubs but they don't really stress community as much as I'd like and we don't really hang out together. Are there any other student orgs or groups that operate in the same way as sororities? In the sense that there is a big emphasis on community development...

I always try and be friendly with people on my floor.. saying hi when we see eachother passing by or trying to talk to people in my classes but everyone already seems to have their group and aren't willing to socialize lol.