Two architecturally/historically significant things are happening today. The first is the groundbreaking ceremony for the Art Institute's new North Wing, designed by Renzo Piano, starting at 8:30am. The second is the awarding of the Pritzker Architecture Prize, held in Millennium Park this evening. I don't mean to be a big geek, but I think I'm going to go. Your handy dandy Slowdown has all the details.