I was five years old when I first visited the Philadelphia Museum of Art.  (way back in 1995).  I remember climbing up hundreds of steps super slowly and then suddenly being surrounded by hundreds of crazy people on roller blades.  My mother was rather nervous about the situation. I remember wondering why they picked this location.  After that day my mother always brought us in the back entrance to the museum, so we wouldn’t be hit by an out-of-control blader.

maybe this is still a popular activity?

I was at the art museum for an Art of India assignment.  I was forced to cross the street and go to the Perelman building to check out a great exhibit on Kantha (embroidered quilts from bengal).  It is a charming but small building that is often neglected by the average museum visitor.  Probably worth a visit if you have mythical free time.