There are three coffeeshops in the city centre that make very good coffees, milkshakes, smooties etc. One is Verdensspeilet World Mirror right opposite the cinema. The second is Syversen Tea And Coffee and the third is Malenki, next to the cinema. All three have friendly staff and great coffee, and are great for a quick bite. If you want to stay a little longer, maybe have a beer and play a boardgame then Verdenspeilet is the best choice.
The riverwalk has a lot of restaurants and bars, and in the summertime, especially, it is a very busy area where people go to eat, drink a beer in the sunshine by the water and in general have a good time. People also come by boat, staying directly at the guest pier.