There are lots of brochures to be had anywhere in Klagenfurt (hotels etc.) what you can do there.
A historical city walk, cycling, museums etc.
take the time to stroll around in town, and visit the lake Worthersee
Fondest memory: The extreme friendliness of the people!
Fondest memory: When I first went to Klagenfurt was to attend my sister beautiful wedding... It was really a great time and I learned a lot of Autrian culture...