Walking, sightseeing and looking in the Woodcarving Shops.
On a clear day in season take the last remaining in Switzerland steam rack railway to the Rothorn - trains depart from the station across the road from the Zentralbahn station. Hotel at the top, sun terraces, and superb views both South over the Bernese Oberland and North as far as Germany. Can get very busy, so go early if you can.
Nearby is also the Ballenberg (http://www.ballenberg.ch/) "swiss open-air museum", showing traditional swiss living.