I'm from Shetland; although it's now part of Scotland, it used to be part of Denmark/Norway. Every year from January to March we have a series of festivals called 'Up Helly 'Aa', the centrepoint of each festival being the burning of a replica Viking Longship by a group of 'guizers' - squads of people in fancy dress, with the main squad being dressed as vikings, with odd pieces of cod-Viking mythology of one sort or another thrown in. It's been going on for about a century now.

There's obviously lots of room for r/badhistory in there (horned and/or winged helmets abound!), but the locals don't really care; we use it as an excuse for drink and mischief more than a serious historical reenactment.

So, there are Norwegian re-enactments of sorts, at least in Scotland. As for what actual Norwegian Norwegians do about their heritage, I'm not sure.

The 1960's saw the revival of Celtic folk music on a larger scale. The first Celtic revival happened late 19th century. At that time people were concerned with collecting old music and tales, mostly. There was this idea of the 'noble savage,' or what have you. Interestingly enough, it was in the Scottish lowlands (that definitively less Celtic part) that really took to the whole Celtic revival and 'reconnecting' with their past.

During the 1960's is when the big revival took place, probably in part due to Celtic music being in direct contrast to the popular music of the time. That being said, Celtic music is also incredibly versatile and I guarantee there is a 'Celtic' inspired song in every genre. Scotland, and Ireland in particular, really just decided "Hey, people like this Celtic stuff! Let's go with it" so they really played it up a bit. Which is not to say that there weren't legitimate efforts at saving the culture, because there were. But a big reason why that has been working is because of the average "modern Celt" (I use that term loosely) wanting to connect to something that was lost.