turnips and radishes

You should check out all the great recipes from the Turnips and Radishes contest http://www.food52.com/contests/293_your_best_radishes_or_turnips

Roast duck with turnips. See J Child in Mastering the Art.

I make a soup (that my kids love) with onions and celery sauteed in butter, turnips, sometimes potatoes, chicken broth, lots of coriander, and cream to finish. Pureed. It's wonderful. My kids also love radishes sliced with butter and salt, and also with sardine butter (recipe somewhere around here).

I love love love turnips. Favorite ways to prepare them: roasted, braised under a roasting chicken, in soup, raw in salads, wilted, pickled (the kimchee idea up top is good but also a fast pickle will do wonderfully.)
Radishes are lovely raw in salsa, gazpacho, crunchy salad, on the shoulders of tacos and eaten out of hand as a snack. But they can also be cooked and I like to saute them with braising greens or grill them a bit. To add to the + butter & nibble answer, I would only add French bread to make a radish & butter tartine.

You can also saute sliced radishes in butter and season with salt and pepper. Toward the end of cooking, add some honey and lemon juice.

And don't forget that the radish greens are edible--add some to a salad or cook them as you would green.

What kind of radishes? If you have the French breakfast radishes or even the usual red radishes, I love to put on a dab of butter and a few grains of sea salt and take a bite. Repeat butter and salt for subsequent bites.

Pickle! I love making a pickle of thinly sliced carrots, radish, and turnips--the liquid should be fairly sweet and tangy with rice vinegar. Also try making some kimchi much as you might make sauerkraut--pack into a crock with salt (1 tbsp salt per 2 pounds produce). Keep the produce submerged beneath the liquid, and in a few weeks you'll have a really delicious fermented pickle.