Have had those crazy Scandinavians on the brain again. Currently about halfway through Burnt Njal's Saga; most of my observations from Egil's Saga apply, though this is more similar to the very late parts of Egil's Saga; much trouble between households and politics at the althing and such. Sort of interesting as a study in the functioning of an effectively-anarchist society with prechristian morality, but not super-gameable.
I also picked up and skimmed Mythic Iceland recently. There were a lot of things I probably won't use (because I'm not running BFRP and doubt I could get buy-in for Runequest), but they had one rule that was pretty interesting. Characters have Luck points, which basically work like action points and aren't recharged. When your PC runs out of luck points, he starts to take additional penalties (beyond just being out of luck points); his neighbors say that he is "luckless", that his time is almost up, and that he has fulfilled his fate, and start avoiding him, because associating with a luckless man can bring no good. So that's a big of an interesting variation on the standard action point system; I guess Dungeon Crawl Classics is sort of similar in that luck is a stat and if you run out you get no bonuses to luck rolls, but I'm not sure it goes quite as far with the penalties.
Also Mythic Iceland's Big Table of Icelandic Names and section on various places in Iceland are pretty good. Oh, and the King of the Polar Bears.
Finally, there was an interesting post on /r/askhistorians about berserkers, and an historian specialising in Norse history made some remarks on how it's likely that berserkers were probably religious warriors associated with animal cults. Thus, if I were to run a norse game, some manner of divinely-powered berserker class might make a good replacement for paladins...