The Guiseppe Meazza (Or San Siro) is a really neat place to visit in Milan.
There is something for everyone, and no matter how crazy of a fan you are you will always learn something! It's a world away from everything else wandering through the museum and stadium. The stadium undergoes heavy construction during the summer to get ready for the season, so don't let that draw your attention elsewhere. By far the best place to go visit while touring Milan.