a) during the week

day: stroll along Bahnhofstrasse and into the old town, don't miss the church with the Chagall windows close to the river
take the train to Lucerne and go on a paddle steamer tour on lake Lucerne or visit the charming town of Lucerne
evening: visit the local pubs in Niederdorf, stay away from the Langstrasse quarter; lot's of places for great food in Niederdorf and Old town

b) weekend

take a train to Chur and connect either to a narrow gauge train to Arosa or St. Moritz, both rides are spectacular

take a train to Lucerne, where you can connect on a narrow gauge railway to Engelberg, go up to Mount Titlis in a (slow) rotating cable car
or go from Lucerne via the Brünig pass to Interlaken