Visit Visit Kristiansand / Kristiansand Turistkontor for some helpful hints before you set out exploring. It's an one-stop shop for travel information.
You'll find this tourist information center in Kristiansand. Once you've done everything you can at Visit Kristiansand / Kristiansand Turistkontor, consider visiting nearby Aquarama Bad, Bystranda, and Kristiansand Cathedral.