LOL Gargoyle! I've crossed the Dan Ryan on foot, but it's pretty safe to do at the UIC bridge.

I have to second the architecture foundation tours and Garrett's popcorn. I worked in the Dirksen building for three years and had to actively exercise my willpower twice a day, every day, when I came out of the subway in front of the Jackson location. The aroma of that caramel in the winter...

I'd also put the Museum of Science and Industry on the list. Generations of Chicago visitors remember seeing the coal mine, the U-505 submarine, walking through the human heart, etc.