Where does one celebrate Jewish holidays in Norway?
In Oslo, Norway where I live there are not many different opportunities to experience and attend Jewish holiday celebrations.

When I grew up, and until very recently the only place to go for Jewish services was the official Jewish community (orthodox).
The first Jews who came to live in Norway founded this community in 1892.
Before WWII, there were two official communities, both traditional orthodox, each with their own synagogue –
After the war, the remaining Jews decided to unite all Jews under one synagogue.
This was the synagogue I grew up belonging to. The Jewish population was heavily marked by losses – almost half of the approx. 1800 Jews were deported and perished in Auschwitz or other camps. The ones who survived had managed to escape to Sweden or elsewhere in time.
As a child I would only attend services for High Holidays and Simchat Torah - only men who were no longer working would attend shabbat morning services everyone else had to work and children go to school.

A lot changed after 1980 - with a new rabbi, a kindergarten that brought families into the fold, shabbes services followed by kiddush (Saturday of from school). I used to attend services regularly at this shul, this is where I learnt to love following the service. Most of what goes on is very traditional. From my place on the women's balcony I was only able to observe what was going on from above. All services were of course in Hebrew only, led by an Israeli cantor - all Siddurim and Machzorim translated into archaic Swedish, Danish or English - nothing in Norwegian ( however the scandinavian languages are very similar and we do mostly understand each other).
The only novel part of any holiday service is the change in nussach and whatever is offered as dvar Torah.
In the 80's and 90’s new melodies were included and sung during most of the mussaf service – Melodies that continue to be used and make the last part of Shabbat morning and holiday services worthwhile coming to (which is what most women and many men do).
At High holidays the former cantor – the one that introduced many of the melodies is invited to come from Israel and lead – and at that time the service is a musical pleasure to be a part of.
I used to be one of two women to sing solo harmonies with the cantor at High holiday services – however in recent years there has been a growing hostility among some of the men against hearing women’s voices that are heard distinctly.

There is now in Oslo a Chabad rabbi (since 2004) who operates from his home offering occational services and holiday celebrations, a group called Progressive Jews of Norway (from 2006) who offer putluck shabbat meals and occasional services and my community Havurat Kol haLev (from 2007) offering monthly kabbalat shabbat as well as some holiday and sahbbatservices with Torah followed by potluck meals.

A newly opened Jewish Museum has the function of being a cultural place and meeting place between Jews and Norwegians.
Many Norwegians with Jewish roots attend their programs.

All in all the official Jewish population of Norway consists of less than 1000 official members of communities – divided between two orthodox synagogues – one in Oslo and one in Trondheim.
It is hard to say how many more Jews there actually are since this is also a question of what criteria one uses, but there are quite a few unaffiliated Jews, mainly Israelis, and Americans and assimilated Norwegian Jews. (Norway has a population of about 5 million).