Pforzheim is on the northern edge of the Black Forest (Schwarzwald) and is the natural rail and road gateway into it. The Enz valley running south is the closest worthwhile outing — Bad Wildbad, with its forest-canopy walk and thermal baths, is 40 minutes by train. The Nagold valley to the south-west reaches the half-timbered towns of Calw (birthplace of Hermann Hesse) and Nagold.
Further afield, Karlsruhe (25 minutes by ICE) has the ZKM media-art centre and one of the most ambitious modern art museums in Germany. Stuttgart is the same distance the other way, with its Staatsgalerie, Mercedes Museum, and Porsche Museum. Baden-Baden is 50 minutes by car or train, for spa towns and old-money atmosphere.