Day trip: Milwaukee or Chi-Town?

In October one of my sales lackies and I will be going on a business trip for a few days at a conference in Milwaukee. I've never been to Milwaukee or really anywhere else in the midwest for that matter. I'm flying in on a Saturday to take some clients out to an expensive dinner, and the conference doesn't start until Monday giving us all Sunday free.

Now, he and I are already talking about plans for the trip. We'll have a few hours each day to spend in Milwaukee but we're still undecided on that Sunday. We already ruled out a football game, as the Packers are in Seattle that day. Then we realized if we're willing to drive the two hours to Lambeau Field, we could just as easily rent a car and drive down to Chicago.

I will not be able to make it to the LAN this year. I'd love to go but the timing is way wrong for me. Perhaps I should wait to post this until after everyone experiences the LAN but we're still in the process of making our plans. However I'll plant the seed now anyway as I'm hoping a couple people from the midwest are reading my blog: Chicago or Milwaukee? And what are some options in either town? The guy I'm going with is my age (29) and is pretty open so finding a mutually agreeable agenda shouldn't be difficult.

He has expressed some interest in the Chicago day trip but if somebody knows of reasons to stay in Milwaukee, we're all ears.