(What is it? "Col nero. An Italian cabbage with very dark, elongated leaves.") What to do with it?? Consult your friendly cookbook - which in my case was the River Cafe Cook Book Green.
The recipe I used was polenta con cavolo nero e salscicce (which I'll post later in the year, when time permits). The result was a (very!) green, creamy polenta that was garlic-y and cheesy without being too rich. The sausages I used went well with it - but I would probably use a more sage-y, spice sausage next time. I compensated for the lack of seasoning in the sausage by using the full amount of bay leaves recommended for 6 servings in our 1/2 recipe. I also added some smoked pancetta towards the end because I particularly like a smokey taste with such dark green cabbage-y vegetables (my Southern American roots shining through and through!). It was delicious, certainly.
The moral of the story is, as always, use your cookbook as a guide for your cooking and always (always) make your own personal mark on everything you cook.