There is SO much to do on campus and around Indy. Obviously, Chicago will have a lot to do as well, but one thing that I like about Indy over Chicago is that Chicago has that big city feel, while Indy has a lot of the advantages of being in a city but you can easily get away from the urban feel.
I don't even know where to begin with on campus activities. A lot of what you decide to do will depend on the organizations you join. There are always a million things to do on the weekends, and most things are free (big plus). Right now, football games on Saturday are popular - later this year it will be basketball. Butler students get into all athletic events for free, and basketball games are AMAZING - by far the best entertainment in the entire city! There are also free movies put on by the student government association every Friday and Saturday night. When the weather is warm, sometimes they put up a big projector on the mall and have a "drive in" movie (we all sit on the grass). The movies are ones that are out of theaters but generally aren't on DVD yet. Last weekend was "Wanted" and they showed "Get Smart" earlier this year. The Greek system also puts on a lot of popular events around campus, often to raise money for charities. Sarah and Joe both have a lot of posts / videos on their blogs, so check it out! As I said before, a lot of my "free" time is taken up with activities for my organization. Next weekend I'm heading to Ohio / Kentucky with my pharmacy fraternity for a big conference. When we're on campus, we sometimes have picnics in Holcomb Gardens (we love to play cornhole and have water balloon fights), or we go to sporting events together (a group went to an Indians Game earlier this year). Butler also sends out a daily e-mail to all students called the "News Digest" where organizations will give announcements about upcoming events on campus.
Indianapolis has a lot of great sports teams, and the awesome thing about them is that tickets are reasonably priced. Last year I went to a Pacers / Bulls game for $15 - the student government association's program board picked up part of the ticket price. I've also been able to go to three Colts games, and I know that tickets to the Indians games are really reasonably priced. If you're into the arts, the IMA is literally just down the street from Butler, and I think that students get in for a discounted price. There are also theatres downtown as well as the ISA (Indianapolis Symphony Orchestra). I know that professors for some classes will utilize these resources and have students attend events - sometimes as an assignment, or sometimes for extra credit. Broad Ripple is an area about 10 minutes from campus where a lot of students go to hang out - there are a lot of restaurants and a few shops. There's a place called Kiln Creations where you can paint your own pottery and it's a lot of fun! Of course we have some really good malls, and there are movie theaters too....basically anything you would expect to find in a city.
I'm a Senior and I still haven't finished exploring Indy - I really want to go check out a lot of the monuments downtown sometime! I've seen most of them from a distance, but I haven't seen them up close.
One more thing - Butler gets a lot of cool concerts, and tickets for students are cheap (think $5 to $10). Ben Folds came to campus my freshman year, and The Fray opened for him. I heard Gavin DeGraw had come for Exam Jam the year before I came to Butler. Last year I went to go see Ok Go (the band that did the really cool treadmill video).
The last awesome thing about the area is that other cities aren't that far away. Even Chicago is only a three hour drive - a lot of students drive up there for the weekend if there's something they really want to do (like a concert or sporting event). Cincinnati is close (2 hours) and you can get to St. Louis in about three hours.