Lutefisk

It used to be served at Grandma and Grandpa's house at Christmas dinner when I was a kid. Grandpa was the one who liked it, and everybody else ate a little to be polite. Haven't had any in probably 55 years or more.

The original reason for lutefisk was food preservation. Cod fillets were hung out on racks to dry in the summer sun and wind, and it took some work (and some lye) to get them back to an edible state.

Gjetost and fattigman are far better Norwegian treats, IMHO.