I think it would be super amazing to teach Muggle Studies as an actual muggle and dispel the weird thoughts and perspectives wizards have on/about non-magical folk. Especially because wizards seem to perceive muggle things as being a different kind magical. It would be a lot of fun to engage in dialogue and figure out what non-magical analogues we have to their spells and how we handle different aspects of society. Question and answer sessions and demonstrations of things that weren't electrical and dressing up and terminology and... and...! heart
In the books, though, doesn't it sound like the class is pretty boring for the students...? Obviously the teacher's doing it wrong!