What are the most uniquely Chicago activities/experiences - good or bad?

I recently returned to Chicago and want to make sure I don't miss any key Chicago experiences before my body gives out. I'll start with some off the top of my head:

• sitting on the concrete 'cliffs' at the Lake in the summer
• sitting in a smoke-filled CTA car
• Chicago handshake at a dive bar
• Italian beef, tavern style pizza, Chicago dog, pizza puff