Generally when I take photos outside my window in River North I am looking East or South. I recently had the opportunity to take a photo from a different condo facing Northwest and picked up a great picture of the sunset on the 4th of July. The main road in front is Ontario which feeds out to the Kennedy / Dan Ryan.
At Millennium Park they have concerts out on the lawn generally on Wednesdays, Fridays and Saturdays. Here is a link to their site with a specific calendar. The "Jay Pritzker Pavillion" is the name of the really cool music shell with the interesting metallic 'roof'. After the show they shine lights on the facility and it changes between a blue and orange. This photo is a view upwards right below the shell looking up at the Aon Building (formerly the Amoco building). I highly recommend these concerts - you can bring food and wine (no beer) and sit out on the lawn with a blanket. No one takes the music too seriously (not like Ravinia where a guy walks around with a "please be quiet" sign and shushes everyone) and you can meet with a group and people from the suburbs can find parking right below the building. Amazingly enough, the restrooms there are even habitable.