The progam “provides free admission to 17 unique cultural destinations throughout the Chicago area to library card holders at over 140 suburban public libraries. This special opportunity is made possible by a generous contribution from Macy’s, the participating cultural organizations, and the DuPage, Metropolitan, and North Suburban Library Systems.”
I did see Brookfield Zoo and Morton Arboretum on the list as places that offer free or discounted rates. Thought I’d mention in case you wanted a zoo day, you could get two free passes to help your expenses.
I saw this mentioned when I was at my local library. I think it goes through 8/31/11, but I can’t be sure.