Sagas of the Icelanders

Colloquially known as "Ragnarok World" is a hack of Apocalypse World by Gregor Vuga, and it's really, really good. If you looked at Ragonarok and thought "I want a more realistic, serious Viking game" then go here to get the current draft of the rules in development.

He was kind enough to mention Ragonarok in his 'ludography', but I'd be pointing you towards it anyway, because it's really exciting to me and does some really clever design stuff. Check it out.