This is free and I can't recommend it highly enough!
Take to Chinatown, walk around, and take the Red Line back up.
They have an alligator snapping turtle named Patsy who is very cool. Her tongue is shaped like and moves like a worm to lure fish.
Always free!
HUGE museum
We haven't actually been here ... but it looks very neat.
They have an interactive coal mine exhibit
Neat store with lots of art prints.