the Chicago Children's Museum is on Navy Pier and is great for all ages. The only negative is the parking - it's expensive (expect to pay about $22), there's no discount, and there's nowhere else to park. However the museum itself is great - small kids will love the grocery store or digging for fossils or the fire engine. Bigger kids will love the construction sets. (ps the photo associated with this is NOT a photo of the Chicago Children's museum)