The American Visionary Art Museum is a fabulous museum of  "Folk Art" right near the inner harbor.  It's really art that is done by untrained / self-taught artists, many of them being disabled/ schizophrenic/ bipolar.   It's completely different than any other art museum you've been to.  It's full of things that are like arts and crafts projects you could do if you had thousands of hours of time.  Completely amazing & mesmerizing.  It's a small museum by the way.  Good for a half-day activity, but not as big as some other attractions.  It's nice though because you can really see everything there.  Even the gift shop is fun.

Link to museum website is here:  American Visionary Art Museum