Here's something else that's great in excess: the library!
Did you know that the Chicago Public Library has a program called Great Kids Museum Passport? This enables us to check out a "Passport", which is a free general admission pass for four, to any of the excellent museums here in the city for free! Wow! Do other cities have this? I've never heard of it anywhere I've lived.
You get what you get - in other words, you look at the chart that shows which passes are in on any given day. Baxter was sad that the Shedd Aquarium, Field Museum, and Adler Planetarium were all checked out today, but I was pretty psyched about the one I got for The Art Institute. It's ours for a week. Of course, I was remembering our schedule incorrectly when I picked one up, and we may not actually get there this week, but I like knowing that if we do, all four of us can get in for free!