What are some fun things to do?

So me and my friend Jessica are going to spend some time together tomorrow. But we don't know what we want to do.. We can't go far, her mom is out of town but left her the car. We want to actually go do something other than the mall. So in Indiana and Illinois, what is there to do? Like where can you go? This is for people that live in the United States. Thanks much. First person to pick where to go that we can actually do, will be chosen best answer!