Dunedin is a small city (population 127,000), but it punches above its weight culturally, making it a fun place to visit for the weekend. There are plenty of galleries, including the Dunedin Public Art Gallery. The Settlers Museum has impressive displays that take you through the development of both Māori and Pākehā culture through the history of Otago.
Everywhere you walk in the city you are likely to come across some fantastic and often enormous street art.
And if you get tired of walking around the city and the cultural sights, you can always stop for a drink.