I remember watching the show as a young teen. Its vague, but I remember him in a medical school class episode. It seems there was also a professor that was supportive of his attending class, though I don't remember if he knew Hank was not enrolled.
Although I only saw a few episodes it had quite an impact on encouraging me toward college. As a teen without much in the way of funding, I tried Hanks method of attending college classes by audit,less the fake mustache. I attended at least 15 classes just to learn the material.(audit without paying used to be pretty easy in the 70s). Professors were always willing to read my papers and let me test. I later earned my BS and graduate degree, and work in emergency medical research and nanotechnology, in part thanks to Hanks example. Thanks Hank!
