If you come to Graz around Christmas time (or in the winter in general), you will want to head down to the center of town in the evening for a few cups of Gluewein (pronounced GLUE-vine) - hot spiced wine served at little stands out on the sidewalk and in the small squares. It is a fine Austrian tradition. Be careful, though.. it goes down awfully easy, especially when it is cold outside. Remember, you have to make the walk home!
A friend of mine made me some here in New York last winter when she came over. Reminded me of skiing in Switzerland and needing a warm "pick me up" mid-day.