I just looked turnips up in Simply in Season:
It says (paraphrsed):
You don't need to peel baby turnips, but you do need to peel turnips with tougher skins.
You can blanche them in boiling water for 4-5 minutes to get rid of a strong or bitter flavor.
You can boil them (15-20 minutes whole turnips) or roast them in the oven or microwave them for 4 minutes.
You can eat turnip greens as well, boiled or steamed.
You can bake them with other sweet vegetables like carrots or parsnips
You can boil them and then puree them with a potato.
Not your Mother's Slow Cooker Cookbook has a recipe for Beef in Guinness with Turnips. (if you get on amazon and search for "guinness" you can probably find it.