Lentils

Skimming through blogs in my google reader, Agricultural Biodiversity pointed me to a post about heirloom cereals in Denmark. Interesting enough stuff but within the text a couple of lines that intrigued and entranced me.

There are apparently lentil varieties that will grow that far north. I've wondered about growing my own but believed they needed a hotter climate for success. Does anyone know more about this? Is there in fact, a usable crop to harvest or are the lentils just a green manure with nitrogen fixing skills? I'd love to know.