There is nice multifunctional Kultur Zentrum in the city centre, right next to the parish church. It is cinema, concert hall, theatre and the exibition hall, all in one. Some guys told me it is a disco club on weekends too.
There is pretty nice city park right in the center of the town, very close to the parish church. Austrians do care alot about the environments, the town of Leibnitz is full of greenery and in particularly its surroundings. Those who love nature and spending peacefull free time in almost idyllic environments will find Leibnitz as a good choice.
It is longtime tradition in Central Europe to eat lots of donuts in the times of a carnival. All city pastry shops must have donuts in their offer during carnival but it is also the tradition to make them at home too. Hosting friends at home cannot be imagine without donuts, and this tradition worth for Austria, Slovenia, Hungary and Croatia.
In the early autumn you can get all sorts of wooden crafted items, animals, dwarfs, human sculptures, gnomes....