The video is poor quality as it was shot with the movie function of my digital camera, but it shows the end of the fireworks display that took place north of the loop on the Chicago River earlier tonight. Looked to be right around Lasalle and Wacker. I have yet to find explanation as to the impetus for the fireworks.
The 2nd video below is actually the first video I took. It's a bit longer, but shows how crazy it was to see fireworks in the middle of the city. Also note the train around the 1:40 mark.
-PJ