Greek life is a great alternative to traditional student housing and will expose you to a lot of different people. At IWU, each of the frats and sororities differ in the kinds of people that join. TKE is full of soccer jocks, Sig Chi has the rest of the jocks, Sig Pi is home to more theater and fine arts majors, and so on. Each house is its own community, and in that sense, they are much like the small halls on campus. The rivalries between frats are played down, though toilet paper occasionally makes its way into the trees from time to time. Feuds within the sororities are sometimes notorious and sometimes petty, but always hilarious.
Greek activities do not extend beyond parties, for the most part. There will be benefit concerts and carwashes and food drives, all of which contribute to this cause or that, but none of which generates considerable interest. You can't always recognize frat guys on the quad, but sorority girls always carry their standard-issue tote emblazoned with the requisite Greek letters. Frat guys are unmistakable at basketball games as they stand right on the sideline and jeer the ref, initiating most of the excitement in the stands. At key times, members' Greek affiliation is evident, but the rest of the day, it's just the place they live.