Oslo fjord, Vigeland Sculpture Park, Skanzen, Viking ship museum, Frammuseum, Royal palace, harbour, etc.

defintely a MUST SEE is the HOLMENKOLLEN, the ski-jump :) go up to the platform and have an amazing view over oslo and the fjords ;)

Vigeland Park is one of the most beautifull things in Oslo, also the Hollmenkollen - You can reach it from metro station near vigeland park, the building of parlament and karl johans gate, the opera building and the bygdoy - near the town hall there is a lovely little harbour - you can take a tourist boat to bygdoy, i recomend You to buy an Oslo pass (it's valid 1,2 or days and it gives you a free acces to most of the museums, public transport and also a lot of discounts f.e at restaurants), form oslo you can go also to drammen - it's not even half an hour by train but you will love this city - so cute! hope this will help you a bit - have a nice stay in norwey!

Vigeland Park, the museum in Bygdøy (Norsk Folkemuseum, Vikingskipshusset), the fjord is nice too

the bay area offers great seafood cuisine and fine dinning after a full day sightseeing.

Definetly the Vigeland Park, go to Akerbrygge, scroll down Karl johan and check out the royal palace... You can check out holmenkollen (specially in the wintertime), check out some of the museums: kon tiki museum, fram museum, childrens museum, technical museum etc. go ice skating dowtown infront of the royal theatre in the wintertime:) and lots and lots more