Your travel itinerary ought to include a visit to University of Passau. It's a well-known local institute with a vibrant campus.
You'll soon learn why this Passau modern university is visited by many travelers. If you're looking for other things to see here, St. Stephan's Cathedral, Old Town Hall, and Kloster Niedernburg are in the area too. They won't take long to get to from University of Passau.