Mellencamp owns a home and recording studio outside the IU campus in Bloomington. Previous guests have included Neil Young, James Brown, Bo Diddley and Cheap Trick’s Rick Nielsen. The singer/songwriter appeared at Professor Glenn Gass’ long-running rock history course, which covers the roots of the genre up through the British invasion. A select group of Indiana University students got an unexpected guest lecturer on Tuesday in the form of Indiana native John Mellencamp.