Often confused with purple-topped turnips, rutabagas are similar but, according to some (this writer, for one), much tastier. Rutabagas are sweeter than their turnip cousins, with a creamier consistency when cooked. In their raw state, rutabaga are also more yellow in hue and oblong in shape. They can be as small as a tight fist or as large as your head—it all depends on the health of the soil in which they were grown, and when they were harvested. Rutabagas can be prepared a variety of ways, from mashed to roasted. Like potatoes, they are no good eaten raw.
Rutabagas sold in the grocery store are often coated with a wax exterior to increase their shelf life. If you're buying those, be sure to peel away the wax and skin before cooking. We prefer rutabagas (and other root veggies) from farmers' markets; those just need to be scrubbed clean before using. Rutabagas are heavy and bulbous, and should feel very firm.
Rutabaga are low-maintenance when it comes to storage. If you've got a root cellar, great—pile 'em in. If, like the rest of us, you're cellar-less, store them loose in a large unsealed plastic bag in the fridge. Don't wash them until just prior to using; moisture and dampness will encourage premature rotting and molding.