This is a very interesting, quirky, museum in Minneapolis. Founded by Earl E. Bakken who invented the first transistorized pacemaker.
Centered around learning about electricity and magnetism there are several exhibits and hands on activities to interest kids and adults. You can play a Thermin [first elcetronic musical instrument], generate a 60,000 volt spark or visit Frankensteins Laboratory.
I agree it isn't huge or overly impressive but is a nice stop to add when checking out a historic neighborhood of Minneapolis or if you are studying the concepts with a class of children.